As filed with the Securities and Exchange Commission on May 27, 2021.

Registration No. 333-            

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM S-1

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

CONTEXT THERAPEUTICS INC.

(Exact name of registrant as specified in its charter)

3675 Market Street, Suite 200

Philadelphia, Pennsylvania 19104

(267) 225-7416

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

Martin Lehr

Chief Executive Officer

3675 Market Street, Suite 200

Philadelphia, Pennsylvania 19104

(267) 225-7416

(Names, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

Approximate date of commencement of proposed sale to public: As soon as practicable after this registration statement becomes effective.

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, check the following box.  ☐

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided to Section 7(a)(2)(B) of the Securities Act.  ☐

CALCULATION OF REGISTRATION FEE

The registrant hereby amends this Registration Statement on such date or dates as may be necessary to delay its effective date until the registrant shall file a further amendment which specifically states that this registration statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933, as amended, or until the registration statement shall become effective on such date as the Securities and Exchange Commission, acting pursuant to said Section 8(a), may determine.

The information contained in this preliminary prospectus is not complete and may be changed. These securities may not be sold until the registration statement filed with the Securities and Exchange Commission is effective. This preliminary prospectus is not an offer to sell these securities and it is not soliciting offers to buy these securities in any state where the offer or sale of these securities is not permitted.

            Shares

Common Stock

Context Therapeutics Inc.

This is the initial public offering of shares of common stock of Context Therapeutics Inc. We currently operate as a Delaware corporation under the name Context Therapeutics Inc. Prior to this offering, there has been no public market for our common stock. We anticipate that the initial public offering price of our shares will be between $                and $                per share.

We have applied to have our common stock listed for trading on the Nasdaq Capital Market under the symbol “CNTX.” Following this offering, we will have one class of common stock.

We are an “emerging growth company” under the federal securities laws and have elected to comply with certain reduced public company reporting requirements.

Investing in our common stock involves a high degree of risk. See “Risk Factors” beginning on page 12 of this prospectus to read about factors you should consider before buying shares of our common stock.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

We have granted the underwriter an option for a period of 45 days from the date of this prospectus to purchase up to an additional                 shares of our common stock to cover over-allotments, if any.

The underwriter expects to deliver the shares to purchasers on or about                , 2021, subject to customary closing conditions.

ThinkEquity

a division of Fordham Financial Management, Inc.

The date of this prospectus is    , 2021

Context Therapeutics Highlights Clinical-stage biopharmaceutical company headquartered in Philadelphia, PA Primary focus on female cancers Up to 70% of breast, ovarian, and endometrial cancers are hormone-dependent Management and advisors have been associated with the development of several FDA approved products (Kisqali(R), Arimidex(R)) for female hormone-dependent cancers Focus on Female Cancers Large Market With Significant Unmet Need Lead Product Candidate in Phase 2 Development Experienced Team

Our Focus on Female Hormone-Dependent Cancers Prevalence of Female, Hormone Driven Cancers in EU5, Japan, and US *Source: secondary epidemiologic estimates, 2020 estimates

TABLE OF CONTENTS

You should rely only on the information contained in this prospectus or contained in any free writing prospectus filed with the Securities and Exchange Commission. Neither we nor the underwriter have authorized anyone to provide any information or to make any representations other than those contained in this prospectus or in any free writing prospectuses we have prepared. Neither we nor the underwriter take responsibility for, and can provide no assurance as to the reliability of, any other information that others may give you. This prospectus is an offer to sell only the shares offered hereby, but only under circumstances and in jurisdictions where it is lawful to do so. The information contained in this prospectus is current only as of its date, regardless of the time of delivery of this prospectus or of any sale of our common stock. Our business, financial condition, results of operations and prospects may have changed since such date.

For investors outside the United States: Neither we nor the underwriter have taken any action to permit this offering or possession or distribution of this prospectus in any jurisdiction where action for that purpose is required, other than in the United States. Persons outside the United States who come into possession of this prospectus must inform themselves about, and observe any restrictions relating to, the offering of the shares of our common stock, and the distribution of this prospectus outside the United States.

INDUSTRY AND MARKET DATA

Unless otherwise indicated, information in this prospectus concerning economic conditions, our industry, our markets and our competitive position is based on a variety of sources, including information from independent industry analysts and publications, as well as our own estimates and research.

Our estimates are derived from publicly available information released by third party sources, as well as data from our internal research, and are based on such data and our knowledge of our industry, which we believe to be reasonable. The independent industry publications used in this prospectus were not prepared on our behalf. While we are not aware of any misstatements regarding any information presented in this prospectus, forecasts, assumptions, expectations, beliefs, estimates and projects involve risk and uncertainties and are subject to change based on various factors, including those described under the headings “Special Note Regarding Forward-Looking Statements” and “Risk Factors.”

TRADEMARKS AND TRADE NAMES

We own or have rights to trademarks, service marks and trade names that we use in connection with the operation of our business. Other trademarks, service marks and trade names appearing in this prospectus are the property of their respective owners. Solely for convenience, some of the trademarks, service marks and trade names referred to in this prospectus are listed without the ^® or ^™ symbols, but we will assert, to the fullest extent under applicable law, our rights to our trademarks, service marks and trade names.

FINANCIAL STATEMENT PRESENTATION

On April 23, 2021, we completed a reverse triangular merger, resulting in Context Therapeutics Inc. becoming the sole holder of 100% of the membership interests in Context Therapeutics LLC, and which resulted in all of the common units, preferred units and all options, warrants or other rights to purchase common or preferred units of Context Therapeutics LLC converting into common stock, preferred stock and all options, warrants or other rights to purchase common or preferred stock of Context Therapeutics Inc. In this prospectus, we refer to this transaction as the “reorganization.”

We have made rounding adjustments to some of the figures included in this prospectus. Accordingly, numerical figures shown as totals in some tables may not be an arithmetic aggregation of the figures that precede them.

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RISK FACTORS

Investing in our common stock involves a high degree of risk. You should consider carefully the risks and uncertainties described below, together with all of the other information in this prospectus, including the section titled “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and our financial statements and related notes, before making a decision to invest in our common stock. Our business, results of operations, financial condition or prospects could also be harmed by risks and uncertainties that are not presently known to us or that we currently believe are not material. If any of the risks actually occur, our business, results of operations, financial condition and prospects could be materially and adversely affected. In that event, the market price of our common stock could decline, and you could lose all or part of your investment.

Risks Related to Our Business and Industry

We have never been profitable and may never achieve or maintain profitability.

We have not commercialized any products and have yet to generate any revenue from product sales. The amount of our future net losses will depend, in part, on our expenses and our ability to generate revenues. Our current and future product candidates will require substantial additional development time and resources before we may realize revenue from product sales, if at all. We expect to continue to incur significant expenses and operating losses for the foreseeable future. We anticipate that our expenses will increase substantially if and as we:

Our first program and lead product candidate, ONA-XR, is currently in Phase 2 clinical trials. No clinical studies have begun on our second program, CLDN6xCD3 bsAb, and our Sigma1 discovery research program is currently in lead optimization and has undergone in vivo studies. It will be several years, if ever, before we obtain regulatory approval for a therapeutic product candidate, at which time any revenues for such product candidate will depend upon many factors, including, market conditions, costs and effectiveness of manufacturing, sales, marketing and distribution operations related to such product candidate, and the terms of any collaboration or other strategic arrangement we may have with respect to such product candidate and levels of reimbursement from third-party payors.

If we are unable to develop and commercialize one or more product candidates either alone or with collaborators, or if revenues from any product candidate that receives marketing approval or is commercialized are insufficient, we may not achieve profitability or sustain profitability, which would have an adverse effect on the value of our common stock which would be materially adversely affected.

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If we are unable to raise substantial additional capital on acceptable terms, or at all, we may be forced to delay, reduce or eliminate some or all of our research programs, product development activities and commercialization efforts.

The process of identifying product candidates and conducting preclinical and clinical trials is time consuming, expensive, uncertain and takes years to complete. Our operations have consumed substantial amounts of cash since inception. We expect our expenses to increase in connection with our ongoing activities, particularly as we identify, continue the research and development of, initiate clinical trials of, and seek marketing approval for, product candidates. In addition, if any therapeutic product candidate that we develop alone or with collaborators obtains marketing approval, we may incur significant commercialization expenses related to product manufacturing, sales, marketing and distribution efforts. Accordingly, we will need to obtain substantial additional funding in connection with our continuing operations. If we are unable to raise sufficient capital when needed, we may be forced to delay, reduce or eliminate current or future research programs, product development activities and/or commercialization efforts.

Adequate additional financing may not be available to us on acceptable terms, or at all. If we are unable to obtain sufficient funding on a timely basis or on favorable terms, we may be required to significantly delay, reduce or eliminate one or more of our research or product development programs and/or commercialization efforts. We may also be unable to expand our operations or otherwise capitalize on business opportunities as desired. Any of these events could materially adversely affect our financial condition and business prospects.

We have a limited operating history, which makes it difficult to evaluate our current business and future prospects and may increase the risk of your investment.

We are a clinical-stage biopharmaceutical company with a limited operating history. We were founded in 2015 and spent the first three years of our company’s history developing and refining our therapeutic approach, and only since then have we focused our efforts on advancing the development of product candidates.

Investment in biopharmaceutical product development is a highly speculative endeavor and entails substantial upfront capital expenditures. There is significant risk that any product candidate will fail to demonstrate adequate efficacy or an acceptable safety profile, obtain any required regulatory approvals or become commercially viable. Our product candidates and the therapeutic approach we are using are new and unproven. We have commenced Phase 2 human clinical trials for one of our product candidates, but have not demonstrated an ability to initiate clinical trials for our other product candidates or successfully complete any clinical trials, obtain any required marketing approvals, manufacture products, conduct sales, marketing and distribution activities, or arrange for a third party to do any of the foregoing on our behalf.

Consequently, any predictions made about our future success or viability may not be as accurate as they could be if we had a history of successfully developing and commercializing products. Our limited operating history, particularly in light of the rapidly evolving nature of the biopharmaceutical industries and the hormone-dependent cancer therapeutics field, may make it difficult to evaluate our technology and business prospects or to predict our future performance.

We may expend our limited resources pursuing particular research programs or product candidates that may be less successful or profitable than other programs or product candidates.

Research programs to identify new product candidates require substantial technical, financial, and human resources. We may focus our efforts and resources on potential programs or product candidates that ultimately prove to be unsuccessful. The successful completion of a clinical trial with regard to any of our product candidates is not assured despite the expenditure of significant resources in pursuit of their development, and our spending on current and future research and development programs and product candidates may not yield any commercially viable products.

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Additionally, if we do not accurately evaluate the commercial potential or target market for a particular product candidate, we may relinquish valuable rights to that product candidate through collaboration, licensing or other strategic arrangements in cases in which it would have been more advantageous for us to retain sole development and commercialization rights to such product candidate.

Our business may be adversely affected by the ongoing coronavirus pandemic.

The outbreak of the novel Coronavirus (“COVID-19”) has evolved into a global pandemic. The extent to which the COVID-19 pandemic impacts our business and operating results will depend on future developments that are highly uncertain and cannot be accurately predicted, including new information that may emerge concerning COVID-19 and the actions to contain the virus or treat its impact, among others.

Should COVID-19 continue to spread, our business operations could be delayed or interrupted. For instance, our research and development may be affected by the pandemic. Site initiation, participant recruitment and enrollment, participant dosing, distribution of clinical trial materials, study monitoring and data analysis may be paused or delayed due to changes in hospital or university policies, federal, state or local regulations, prioritization of hospital resources toward pandemic efforts, or other reasons related to the pandemic. If COVID-19 continues to spread, some participants and clinical investigators may not be able to comply with clinical trial protocols. For example, quarantines or other travel limitations (whether voluntary or required) may impede participant movement, affect sponsor access to study sites, or interrupt healthcare services, and we may be unable to conduct our research activities, including clinical trials.

Infections and deaths related to the pandemic have disrupted and may continue to disrupt the United States’ healthcare and healthcare regulatory systems. Such disruptions could divert healthcare resources away from, or materially delay FDA review and/or approval. It is unknown how long these disruptions could continue, were they to occur. Any elongation or de-prioritization of clinical trials or delay in regulatory review resulting from such disruptions could materially affect the development and study of our product candidates.

In the event of a shelter-in-place order or other mandated local travel restrictions, our employees and consultants conducting research and development or manufacturing activities may not be able to access their laboratory or manufacturing space, and our core activities may be significantly limited or curtailed, possibly for an extended period of time.

The spread of COVID-19, which has caused a broad impact globally, including restrictions on travel and quarantine policies put into place by businesses and governments, may have a material economic effect on our business. New or renewed restrictions may be implemented in response to evolving conditions and overall uncertainty about the timing of widespread availability of vaccines. While the potential economic impact brought by and the duration of the pandemic may be difficult to assess or predict, it has already caused, and is likely to result in further, significant disruption of global financial markets, which may reduce our ability to access capital either at all or on favorable terms. In addition, a recession, depression or other sustained adverse market event resulting from the spread of COVID-19 could materially and adversely affect our business and the value of our common stock.

The ultimate impact of the current pandemic, or any other health epidemic, is highly uncertain and subject to change. We do not yet know the full extent of potential delays or impacts on our business, our clinical trials, our research programs, healthcare systems or the global economy as a whole. However, these effects could have a material impact on our operations, and we will continue to monitor the situation closely.

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Our governing documents designate the Court of Chancery of the State of Delaware as the sole and exclusive forum for certain types of state law actions and proceedings that may be initiated by our stockholders, which could limit our stockholders’ ability to obtain a favorable judicial forum for disputes with us or our directors, officers, employees or agents.

Our amended & restated certificate of incorporation will provide that, unless we consent in writing to the selection of an alternative form, the Court of Chancery of the State of Delaware (or, if the Court of Chancery does not have jurisdiction, the United States District Court for the District of Delaware) will be the sole and exclusive forum for: (1) any derivative action or proceeding brought on our behalf; (2) any action asserting a claim of breach of a fiduciary duty or other wrongdoing by any of our directors, officers, employees or agents to us or our shareholders; (3) any action asserting a claim against us arising pursuant to any provision of the General Corporation Law of the State of Delaware or our amended & restated certificate of incorporation or amended & restated bylaws; (4) any action to interpret, apply, enforce or determine the validity of our amended & restated certificate of incorporation or amended & restated bylaws; or (5) any action asserting a claim governed by the internal affairs doctrine. In addition, our amended & restated certificate of incorporation will provide that, unless we consent in writing to the selection of an alternative forum, the federal district courts of the United States of America shall, to the fullest extent permitted by law, be the sole and exclusive forum for the resolution of any complaint asserting a cause of action arising under the Securities Act. Notwithstanding the foregoing, the exclusive forum provision shall not apply to claims seeking to enforce any liability or duty created by the Exchange Act.

This choice of forum provision may limit our stockholders’ ability to bring a claim in a judicial forum that it finds favorable for disputes with us or our directors, officers, employees or agents, which may discourage such lawsuits against us and our directors, officers, employees and agents even though an action, if successful, might benefit our stockholders. Stockholders who do bring a claim in the Court of Chancery could face additional litigation costs in pursuing any such claim, particularly if they do not reside in or near Delaware. The Court of Chancery may also reach different judgments or results than would other courts, including courts where a stockholder considering an action may be located or would otherwise choose to bring the action, and such judgments or results may be more favorable to us than to our stockholders. Alternatively, if a court were to find this provision inapplicable to, or unenforceable in respect of, one or more of the specified types of actions or proceedings, we may incur additional costs associated with resolving such matters in other jurisdictions, which could have a material adverse effect on our business, financial condition or results of operations.

Risks Related to our Product Candidates

Our business is dependent on the successful development, regulatory approval and commercialization of our therapeutic product candidates, ONA-XR and CLDN6xCD3 bsAb, which are in the early stages of development.

We have no products approved for sale. The success of our business, including our ability to finance our company and generate any revenue in the future, will primarily depend on the successful development, regulatory approval and commercialization of ONA-XR and CLDN6xCD3 bsAb, as well as other product candidates derived from our anti-hormone resistant therapy approach, which may never occur.

In the future, we may also become dependent on other product candidates that we may develop or acquire; however, not all of our product candidates have been tested in humans and given our early stage of development, it may be many years, if at all, before we have demonstrated the safety and efficacy of a hormone-dependent cancer treatment sufficient to warrant approval for commercialization.

We have not previously submitted a new drug application (“NDA”) or biologics license application (“BLA”), to the FDA or similar regulatory approval filings to comparable foreign authorities, for any product candidate, and we cannot be certain that our product candidates will be successful in clinical trials or receive regulatory approval. Further, any future product candidates may not receive regulatory approval even if they are

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successful in clinical trials. If we do not receive regulatory approvals for our product candidates, we may not be able to continue our operations. Even if we successfully obtain regulatory approvals to market a product candidate, our revenue will be dependent, in part, upon the size of the markets in the territories for which we gain regulatory approval and have commercial rights. If the markets or patient subsets that we are targeting are not as significant as we estimate, we may not generate significant revenues from sales of such products, if approved.

We plan to seek regulatory approval to commercialize our product candidates both in the United States and in selected foreign countries. While the scope of regulatory approval generally is similar in other countries, in order to obtain separate regulatory approval in other countries we must comply with numerous and varying regulatory requirements of such countries regarding safety and efficacy. Other countries also have their own regulations governing, among other things, clinical trials and commercial sales, as well as pricing and distribution of our product candidates, and we may be required to expend significant resources to obtain regulatory approval and to comply with ongoing regulations in these jurisdictions.

The clinical and commercial success of our current and any future product candidates will depend on a number of factors, including the following:

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These factors, many of which are beyond our control, could cause us to experience significant delays or an inability to obtain regulatory approvals or commercialize our current or future product candidates. Even if regulatory approvals are obtained, we may never be able to successfully commercialize any product candidates. Accordingly, we cannot provide assurances that we will be able to generate sufficient revenue through the sale of our product candidate or any future product candidates to continue our business or achieve profitability.

Our innovative therapy approach is based on novel ideas and technologies that are unproven and may not result in marketable products, which exposes us to unforeseen risks and makes it difficult for us to predict the time and cost of product development and potential for regulatory approval.

Our foundational science and product development approach are based on the selective targeting of hormone-dependent cancers, including by inhibiting progesterone receptor binding to chromatin, and by inhibiting CLDN6, in each case to elicit meaningful anticancer activity. We believe that this approach may offer an improved therapeutic effect by downregulating PR effector functions associated with anti-estrogen resistant and inhibit tumor growth, as well as redirect T-cell-mediated lysis toward malignant cells expressing CLDN6. However, this approach to treating cancer is novel and the scientific research that forms the basis of our efforts to develop therapeutics that effectively target anti-hormone treatment resistance and inhibit membrane protein targets is both preliminary and limited.

As such, we cannot assure you that even if we are able to develop cancer therapeutic candidates capable of addressing anti-estrogen resistance or redirecting T-cell-mediated lysis toward malignant cells, that such therapy would safely and effectively treat cancers. We may spend substantial funds attempting to develop this approach and never succeed in developing a marketable therapeutic.

Furthermore, no regulatory authority has granted approval for a cancer therapy based on a selective targeting of PR+ or Claudin 6 positive cancers. As such, we believe the FDA has limited experience with evaluating our approach, which may increase the complexity, uncertainty and length of the regulatory approval process for our product candidates. We may never receive approval to market and commercialize any product candidate. Even if we obtain regulatory approval, the approval may be for targets, disease indications, lines of therapy or patient populations that are not as broad as we intended or desired or may require labeling that includes significant use or distribution restrictions or safety warnings.

Results of preclinical studies, early clinical trials or analyses may not be indicative of results obtained in later trials.

The results of preclinical studies, early clinical trials or analyses of our product candidates may not be predictive of the results of later-stage clinical trials. Product candidates in later stages of clinical trials may fail to show the desired safety and efficacy traits despite having progressed through preclinical studies and initial clinical trials. A number of companies in the biopharmaceutical industry have suffered significant setbacks in advanced clinical trials due to lack of efficacy or adverse safety profiles, notwithstanding promising results in earlier trials. In addition, conclusions based on promising data from analyses of clinical results may be shown to be incorrect when implemented in prospective clinical trials. Even if our ongoing clinical trials for ONA-XR and future clinical trials for our other product candidates are completed as planned, we cannot be certain that their results will support the safety and efficacy sufficient to obtain regulatory approval.

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Interim “top-line” and preliminary data from our clinical trials that we announce or publish from time to time may change as more patient data become available and are subject to audit and verification procedures that could result in material changes in the final data.

From time to time, we may publish interim “top-line” or preliminary data from our clinical studies. Interim data from clinical trials that we may complete are subject to the risk that one or more of the clinical outcomes may materially change as patient enrollment continues and more patient data become available. Preliminary or “top-line” data also remain subject to audit and verification procedures that may result in the final data being materially different from the preliminary data we previously published. As a result, interim and preliminary data should be viewed with caution until the final data are available. Adverse differences between preliminary or interim data and final data could significantly harm our business prospects.

Our product candidates may cause serious adverse events or undesirable side effects, which may delay or prevent marketing approval, or, if approved, require them to be taken off the market, require them to include safety warnings or otherwise limit their sales.

Serious adverse events or undesirable side effects caused by ONA-XR, CLDN6xCD3 bsAb or any other product candidates could cause us or regulatory authorities to interrupt, delay or halt clinical trials and could result in a more restrictive label or the delay or denial of regulatory approval by the FDA or other comparable foreign authorities. Results of any clinical trial we conduct could reveal a high and unacceptable severity and prevalence of side effects or unexpected characteristics. Patients treated with ONA-XR to date, at high doses have experienced adverse events that include, but are not limited to, fatigue, liver enzyme elevations and nausea.

If unacceptable side effects arise in the development of our product candidates, we, the FDA or the institutional review boards at the institutions in which our studies are conducted, or the data safety monitoring board, if constituted for our clinical trials, could recommend a suspension or termination of our clinical trials, or the FDA or comparable foreign regulatory authorities could order us to cease further development of or deny approval of a product candidate for any or all targeted indications. In addition, drug-related side effects could affect patient recruitment or the ability of enrolled patients to complete a trial or result in potential product liability claims. In addition, these side effects may not be appropriately recognized or managed by the treating medical staff. We expect to have to train medical personnel using our product candidates to understand the side effect profiles for our clinical trials and upon any commercialization of any of our product candidates. Inadequate training in recognizing or managing the potential side effects of our product candidates could result in patient injury or death. Any of these occurrences may harm our business, financial condition and prospects significantly.

Additionally, if one or more of our product candidates receives marketing approval, and we or others later identify undesirable side effects caused by such products, a number of potentially significant negative consequences could result, including:

Any of these events could prevent us from achieving or maintaining market acceptance of a product candidate, if approved, and could significantly harm our business, results of operations and prospects.

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The success of our business depends primarily upon our ability to identify, develop and commercialize products using our proprietary technologies.

Besides our ONA-XR product candidate, all of our current product candidates and product development programs are still in the IND validation process. We may be unsuccessful in advancing those product candidates into clinical development or in identifying and developing additional product candidates.

Our ability to identify and develop product candidates is subject to the numerous risks associated with preclinical and early stage biopharmaceutical development activities, including that:

Even if we do commence additional clinical trials of product candidates and continue to identify new product candidates, such product candidates may never be approved. Failure to successfully identify and develop new product candidates and obtain regulatory approvals for our products would have a material adverse effect on our business and financial condition and could cause us to cease operations.

If our product candidates do not achieve projected development milestones or commercialization in the announced or expected timeframes, the further development or commercialization of such product candidates may be delayed, and our business will be harmed.

We sometimes estimate, or may in the future estimate, the timing of the accomplishment of various scientific, clinical, manufacturing, regulatory and other product development objectives. These milestones may include our expectations regarding the commencement or completion of scientific studies or clinical trials, the submission of regulatory filings, the receipt of marketing approval or the realization of other commercialization objectives.

The achievement of many of these milestones may be outside of our control. All of these milestones are based on a variety of assumptions, including assumptions regarding capital resources, constraints and priorities, progress of and results from development activities and the receipt of key regulatory approvals or actions, any of which may cause the timing of achievement of the milestones to vary considerably from our estimates.

If our collaborators or ourselves fail to achieve announced milestones in the expected timeframes, the commercialization of the product candidates may be delayed, our credibility may be undermined, our business and results of operations may be harmed, and the price of our common stock may decline.

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Product liability lawsuits against us could cause us to incur substantial liabilities and could limit commercialization of any products that we develop alone or with collaborators.

We face an inherent risk of product liability and professional indemnity exposure related to the testing in clinical trials of our product candidates. We will face an even greater liability risk if we commercially sell any products that we or our collaborators may develop for human use.

Manufacturing defects, errors in product distribution or storage processes, improper administration or application and known or unknown side effects of product usage may result in liability claims against us or third parties with which we have relationships. These actions could include claims resulting from acts by our collaborators, licensees and subcontractors over which we have little or no control. For example, our liability could be sought by patients participating in clinical trials for potential therapeutic product candidates as a result of unexpected side effects, improper product administration or the deterioration of a patient’s condition, patient injury or even death.

Criminal or civil proceedings might be filed against us by patients, regulatory authorities, biopharmaceutical companies and any other third party using or marketing any product candidates or products that we develop alone or with collaborators. On occasion, large judgments have been awarded in class action lawsuits based on products that had unanticipated adverse effects. If we cannot successfully defend ourselves against claims that product candidates or products we develop alone or with collaborators caused harm, we could incur substantial liabilities.

Clinical development does not always fully characterize the safety and efficacy profile of a new medicine, and it is always possible that a drug or biologic, even after regulatory approval, may exhibit unforeseen side effects. If our product candidates were to cause adverse side effects during clinical trials or after approval, we may be exposed to substantial liabilities.

Product liability insurance coverage may not be adequate to cover all liabilities that we may incur. We anticipate that we will need to increase our insurance coverage when we expand our clinical trials and if our collaborators or ourselves successfully commercialize any products.

Risks Related to Our Organization, Structure and Operations

Our reliance on a central team consisting of a limited number of employees and consultants who provide various administrative, research and development, and other services across our organization presents operational challenges that may adversely affect our business.

As of April 30, 2021, we had two full-time employees. We also have three consultants who we rely on for research and development, business development and other services. While we believe this structure enables us to reduce certain infrastructure costs, the small size of our centralized team may limit our ability to devote adequate personnel, time and resources to support the operations of our business, including our research and development activities, and the management of financial, accounting and reporting matters. If our centralized team fails to provide adequate administrative, research and development, or other services across our entire organization, our business, financial condition and results of operations could be harmed.

Our future success depends on our ability to retain our Chief Executive Officer, Chief Legal Officer, Chief Medical Officer, Senior Vice President of Research and Development, Head of Chemistry Manufacturing Controls (“CMC”) and Regulatory, and other key executives and to attract, retain and motivate qualified personnel.

We are highly dependent on the research and development experience, technical skills, leadership and continued service of certain members of our management and scientific teams, including Martin Lehr, our Chief Executive Officer, Alex Levit, our Chief Legal Officer, Tarek Sahmoud, our Chief Medical Officer, Evan Dick, our Senior Vice President of Research and Development, and Bill Rencher, our Head of CMC and Regulatory.

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Although we have formal employment agreements and consulting agreements with our executive officers, these agreements do not prevent them from terminating their employment with us at any time. The loss of the services of any of these persons could impede the achievement of our research, development and commercialization objectives.

Recruiting and retaining qualified scientific, clinical, manufacturing and, if we retain commercialization responsibility for any product candidate we develop alone or with collaborators, sales and marketing personnel, will also be critical to our success. We may not be able to attract and retain these personnel on acceptable terms or at all given the competition among numerous pharmaceutical and biotechnology companies for similar personnel. We also experience competition for the hiring of scientific and clinical personnel from universities and research institutions. In addition, we rely on consultants and advisors, including scientific and clinical advisors, to assist us in formulating our research and development and commercialization strategies. Our consultants and advisors may be employed by employers other than us and may have commitments under consulting or advisory contracts with other entities that may limit their availability to us.

The inability to recruit, integrate, motivate and retain additional skilled and qualified personnel, or the loss of services of certain executives, key employees, consultants or advisors, may impede the progress of our research, development and commercialization objectives and have a material adverse effect on our business.

We will need to expand our organization, and we may experience difficulties in managing this growth, which could disrupt our operations.

We will need to significantly expand our organization, and our future financial performance, ability to develop and commercialize product candidates alone or with collaborators and ability to compete effectively will depend in part on our ability to effectively manage any future growth. We may have difficulty identifying, hiring and integrating new personnel.

Many of the biopharmaceutical companies that we compete against for qualified personnel and consultants have greater financial and other resources, different risk profiles and a longer history than we do. If we are unable to continue to attract and retain high-quality personnel and consultants, the rate and success at which we can identify and develop product candidates, enter into collaborative arrangements and otherwise operate our business will be limited.

Future growth would impose significant additional responsibilities on our management, including the need to identify, recruit, maintain, motivate and integrate additional employees, consultants and contractors. Management may need to divert a disproportionate amount of its attention away from our day-to-day activities and devote a substantial amount of time to managing these growth activities. Due to our limited financial resources and the limited experience of our management team in managing a company with such anticipated growth, we may not be able to effectively manage the expected expansion of our operations or recruit and train additional qualified personnel.

Moreover, the expected physical expansion of our operations may lead to significant costs and may divert our management and business development resources from other projects, such as the development of product candidates. If we are not able to effectively manage the expansion of our operations, it may result in weaknesses in our infrastructure, increase our expenses more than expected, give rise to operational mistakes, loss of business opportunities, loss of employees, consultants and contractors and reduced productivity.

Our insurance policies are expensive and protect us only from some business risks, which leaves us exposed to significant uninsured liabilities.

We do not carry insurance for all categories of risk that our business may encounter. If we obtain marketing approval for any product candidates that we or our collaborators may develop, we intend to acquire insurance coverage to include the sale of commercial products, but we may be unable to obtain such insurance on

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commercially reasonable terms or in adequate amounts. We do not carry specific biological or hazardous waste insurance coverage, and our property, casualty and general liability insurance policies specifically exclude coverage for damages and fines arising from biological or hazardous waste exposure or contamination.

Accordingly, in the event of contamination or injury, we could be held liable for damages or be penalized with fines in an amount exceeding our resources, and clinical trials or regulatory approvals for any of our product candidates could be suspended. We also expect that operating as a public company will make it more expensive for us to obtain director and officer liability insurance, and we may be required to accept reduced policy limits and coverage or incur substantially higher costs to obtain the same or similar coverage. As a result, it may be more difficult for us to attract and retain qualified individuals to serve on our board of directors, our board committees or as our executive officers.

Insurance coverage is becoming increasingly expensive, and in the future, we may not be able to maintain insurance coverage at a reasonable cost or in sufficient amounts to protect us against losses. We do not know if we will be able to maintain existing insurance with adequate levels of coverage, and any liability insurance coverage we acquire in the future may not be sufficient to reimburse us for any expenses or losses we may suffer. A successful liability claim or series of claims brought against us could require us to pay substantial amounts and cause our share price to decline and, if judgments exceed our insurance coverage, could adversely affect our results of operations and business, including preventing or limiting the development and commercialization of any product candidates that we or our collaborators may develop.

Risks Related to Our Reliance on Third Parties

We expect to depend on collaborations with third parties for certain research, development and commercialization activities, and if any such collaborations are not successful, it may harm our business and prospects.

Working with collaborators poses several significant risks, including the following:

Our ability to generate revenues from these arrangements will depend on our collaborators’ abilities to successfully perform the functions assigned to them in these arrangements. If our collaborations do not result in the successful development and commercialization of product candidates, or if one of our collaborators terminates its agreement with us, we may not receive the expected deliverables or services from our collaborators, nor receive any future funding or milestone or royalty payments under the collaboration.

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If we do not receive the funding or expected deliverables or services from our collaborators, we expect under these agreements, our development of product candidates could be delayed, and we may need additional resources to develop such product candidates. In addition, if one of our collaborators terminates its agreement with us, we may find it more difficult to find a suitable replacement collaborator or attract new collaborators and may need to raise additional capital to pursue further development or commercialization of the applicable product candidates.

These events could delay development programs and negatively impact the perception of our company in business and financial communities. Failure to develop or maintain relationships with any current collaborators could result in the loss of opportunity to work with that collaborator or reputational damage that could impact our relationships with other collaborators in the relatively small industry communities in which we operate.

Moreover, all of the risks relating to product development, regulatory approval and commercialization described in this prospectus apply to the activities of our collaborators. If our existing collaboration agreements or any collaborative or strategic relationships we may establish in the future are not effective and successful, it may damage our reputation and business prospects, delay or prevent the development and commercialization of product candidates and inhibit or preclude our ability to realize any revenues.

We have relied on and we expect to continue to rely on third parties to conduct, supervise and monitor our clinical trials and some aspects of our research and preclinical testing, and if those third parties do not successfully carry out their contractual duties, comply with regulatory requirements, or otherwise perform in a satisfactory manner, we may not be able to obtain regulatory approval or commercialize product candidates, or such approval or commercialization may be delayed, and our business may be substantially harmed.

We have relied on and we expect to continue to rely on medical institutions, clinical investigators, contract laboratories and other third parties, such as contract research organizations (“CROs”) to conduct preclinical studies and clinical trials for our product candidates. Nevertheless, we are responsible for ensuring that each of our studies and trials is conducted in accordance with the applicable protocol, legal and regulatory requirements and scientific standards, and our reliance on such third parties will not relieve us of our regulatory responsibilities. For example, we remain responsible for ensuring that each of our clinical trials is conducted in accordance with the general investigational plan and protocols for the trial. Moreover, the FDA requires us to comply with regulations, commonly referred to as good clinical practices, or GCPs, for conducting, monitoring, recording and reporting the results of clinical trials to assure that data and reported results are credible and accurate and that the rights, integrity and confidentiality of trial participants are protected.

Although we have designed and intend to design future trials for our product candidates either alone or with collaborators, third parties may conduct all of the trials. As a result, many important aspects of our research and development programs, including their conduct and timing, will be outside of our direct control. Our reliance on third parties to conduct future studies and trials will also result in less direct control over the management of data developed through studies and trials than would be the case if we were relying entirely upon our own staff. Communicating with outside parties can also be challenging, potentially leading to mistakes and difficulties in coordinating activities. Such third parties may have staffing difficulties, fail to comply with contractual obligations, experience regulatory compliance issues, undergo changes in priorities, become financially distressed or form relationships with other entities, some of which may be our competitors.

We also face the risk of potential unauthorized disclosure or misappropriation of our intellectual property by CROs or other third parties, which may reduce our trade secret protection and allow our potential competitors to access and exploit our proprietary technology. For any violations of laws and regulations during the conduct of our preclinical studies and clinical trials, we could be subject to warning letters or enforcement action that may include civil penalties up to and including criminal prosecution.

If we, our collaborators, our CROs or other third parties fail to comply with applicable GCPs, the clinical data generated in our clinical trials may be deemed unreliable and FDA or comparable foreign regulatory authorities may require us to perform additional clinical trials before approving our marketing applications. We

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also are required to register certain ongoing clinical trials and post the results of such completed clinical trials on a government-sponsored database, within certain timeframes. Failure to do so can result in fines, adverse publicity and civil and criminal sanctions.

If our CROs or other third parties do not successfully carry out their contractual duties or obligations, fail to meet expected deadlines, or if the quality or accuracy of the clinical data they obtain is compromised due to the failure to adhere to our clinical protocols or regulatory requirements or for any other reasons, trials for product candidates may be extended, delayed or terminated, and we or our collaborators may not be able to obtain regulatory approval for, or successfully commercialize, any product candidate that we develop. If we are required to repeat, extend the duration of or increase the size of any trials we conduct, it could significantly delay commercialization and require significantly greater expenditures.

As a result of any of these factors, our financial results and the commercial prospects for any product candidate that we or our collaborators may develop would be harmed, our costs could increase and our ability to generate revenues could be delayed.

If we are unable to obtain sufficient quantities of raw materials and supplies, at acceptable prices and on a timely basis, it could harm our business.

We are dependent on third parties for the supply of various pharmaceutical and biological materials and the manufacture of product supplies that are necessary to produce our product candidates. The supply of these materials could be reduced or interrupted at any time. In such case, identifying and engaging an alternative supplier or manufacturer could result in delay, and we may not be able to find other acceptable suppliers or manufacturers on acceptable terms, or at all.

Changing suppliers or manufacturers may involve substantial costs and is likely to result in a delay in our desired clinical and commercial timelines. If we change suppliers or manufacturers for commercial production, applicable regulatory agencies may require us to conduct additional studies or trials. If key suppliers or manufacturers are lost, or if the supply of the materials is diminished or discontinued, we or our collaborators may not be able to develop, manufacture and market product candidates in a timely and competitive manner, or at all. If any of our product candidates receives approval, we will likely need to seek alternative sources of supply of raw materials or manufactured product supplies and there can be no assurance that we will be able to establish such relationships to provide such supplies on commercially reasonable terms or at acceptable quality levels, if at all. If we are unable to identify and procure additional sources of supply that fit our required needs, we could face substantial delays or incur additional costs in procuring such materials.

We may rely on third parties for the manufacturing process of product candidates, and failure by those parties to adequately perform their obligations could harm our business.

We do not currently own any facility that may be used as our clinical-scale manufacturing and processing facility and expect that we will rely on outside vendors for at least a portion of the manufacturing process of product candidates that we or our collaborators may develop. The facilities used by our contract manufacturers to manufacture product candidates must be approved by the FDA or other foreign regulatory agencies pursuant to inspections that will be conducted after we submit an application to the FDA or other foreign regulatory agencies. To the extent that we or our collaborators engage third parties for manufacturing services, we will not control the manufacturing process of, and will be completely dependent on, our contract manufacturing providers for compliance with cGMP requirements for manufacture of the product candidates.

We have not yet caused any product candidates to be manufactured or processed on a commercial scale and may not be able to do so. We will make changes as we work to optimize the manufacturing process, and we cannot be sure that even minor changes in the process will result in products that are safe and effective. If our contract manufacturers cannot successfully manufacture material that conforms to our specifications and the

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strict regulatory requirements of the FDA or other regulatory authorities, they will not be able to secure and/or maintain regulatory approval for their manufacturing facilities. In addition, we have no control over the ability of our contract manufacturers to maintain adequate quality control, quality assurance and qualified personnel.

If the FDA or a comparable foreign regulatory authority does not approve these facilities for the manufacture of product candidates or if it withdraws any such approval in the future, we may need to find alternative manufacturing facilities, which would significantly impact our ability to develop, obtain regulatory approval for or market any of our or our collaborators’ potential products.

If we are not able to establish collaborations on commercially reasonable terms, we may have to alter our research, development and commercialization plans.

Our research and product development programs and the potential commercialization of our product candidates will require substantial additional cash to fund expenses, and we expect that we will continue to seek collaborative arrangements for the development and potential commercialization of current and future product candidates or the development of ancillary technologies.

We face significant competition in establishing relationships with appropriate collaborators. In addition, there have been a significant number of recent business combinations among large pharmaceutical companies that have resulted in a reduced number of potential future collaborators. Whether we reach a definitive agreement for a collaboration will depend, among other things, upon our assessment of the collaborator’s resources and expertise, the terms and conditions of the proposed collaboration and the proposed collaborator’s evaluation of a number of factors. Those factors may include, among other things and as applicable for the type of potential product, an assessment of the opportunities and risks of our product candidate, the design or results of studies or trials, the likelihood of approval, if necessary, by the USDA, the FDA or similar regulatory authorities outside the United States, the potential market for the subject product candidate, the costs and complexities of manufacturing and delivering such product candidate to patients, the potential of competing products and industry and market conditions generally.

Collaborations are complex and time-consuming to negotiate and document. We may not be able to negotiate collaborations on a timely basis, on acceptable terms, or at all. If we do enter into additional collaboration agreements, the negotiated terms may force us to relinquish rights that diminish our potential profitability from development and commercialization of the subject product candidates or others. If we are unable to enter into additional collaboration agreements, we may have to curtail the research and development of the product candidate for which we are seeking to collaborate, reduce or delay research and development programs, delay potential commercialization timelines, reduce the scope of any sales or marketing activities or undertake research, development or commercialization activities at our own expense.

Risks Related to Government Regulation

The FDA regulatory approval process is lengthy and time-consuming, and we may experience significant delays in the clinical development and regulatory approval of our product candidates.

The research, testing, manufacturing, labeling, approval, selling, import, export, marketing, and distribution of drug products, including biologics and pharmaceuticals, are subject to extensive regulation by the FDA and other regulatory authorities in the United States. We expect the novel nature of our product candidates to create further challenges in obtaining regulatory approval. For example, the FDA has limited experience with commercial development of anti-estrogen resistance inhibition therapies for cancer. The FDA may also require a panel of experts, referred to as an Advisory Committee, to deliberate on the adequacy of the safety and efficacy data to support licensure. The opinion of the Advisory Committee, although not binding, may have a significant impact on our ability to obtain licensure of the product candidates based on the completed clinical trials, as the FDA often makes decisions consistent with the Advisory Committee’s recommendations. Accordingly, the regulatory approval pathway for our product candidates may be uncertain, complex, expensive and lengthy, and approval may not be obtained.

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We may also experience delays in completing planned clinical trials for a variety of reasons, including delays related to:

We could also encounter delays if physicians encounter unresolved ethical issues associated with enrolling patients in clinical trials of our product candidates in lieu of prescribing existing treatments that have established safety and efficacy profiles. Further, a clinical trial may be suspended or terminated by us, the IRBs for the institutions in which such trials are being conducted or by the FDA or other regulatory authorities due to a number of factors, including failure to conduct the clinical trial in accordance with regulatory requirements or our clinical protocols, inspection of the clinical trial operations or trial site by the FDA or other regulatory authorities resulting in the imposition of a clinical hold, unforeseen safety issues or adverse side effects, failure to demonstrate a benefit from using a product candidate, changes in governmental regulations or administrative actions, lack of adequate funding to continue the clinical trial, or based on a recommendation by the Data Safety Monitoring Committee. The FDA’s review of our data of our ongoing clinical trials may, depending on the data, also result in the delay, suspension or termination of one or more clinical trials, which would also delay or prevent the initiation of our other planned clinical trials. If we experience termination of, or delays in the completion of, any clinical trial of our product candidates, the commercial prospects for our product candidates will be harmed, and our ability to generate product revenue will be delayed. In addition, any delays in completing our clinical trials will increase our costs, slow down our product development and approval process and jeopardize our ability to commence product sales and generate revenue.

Many of the factors that cause, or lead to, a delay in the commencement or completion of clinical trials may ultimately lead to the denial of regulatory approval of our product candidates.

We expect that CLDN6xCD3 bsAb will be regulated as biological products, or biologics, and therefore they may be subject to competition sooner than anticipated.

The Biologics Price Competition and Innovation Act was enacted as part of the Affordable Care Act to establish an abbreviated pathway for the approval of biosimilar and interchangeable biological products. The regulatory pathway establishes legal authority for the FDA to review and approve biosimilar biologics, including the possible designation of a biosimilar as “interchangeable” based on its similarity to an approved biologic. Under the Biologics Price Competition and Innovation Act, an application for a biosimilar product cannot be approved by the FDA until 12 years after the reference product was approved under a BLA. The law is complex

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and is still being interpreted and implemented by the FDA. As a result, its ultimate impact, implementation, and meaning are subject to uncertainty. While it is uncertain when such processes intended to implement the Biologics Price Competition and Innovation Act may be fully adopted by the FDA, any such processes could have a material adverse effect on the future commercial prospects for our biological products.

We believe that CLDN6xCD3 bsAb, if approved in the United States as a biological product under a BLA should qualify for the 12-year period of exclusivity. However, there is a risk that this exclusivity could be shortened due to congressional action or otherwise, or that the FDA will not consider the subject product candidates to be reference products for competing products, potentially creating the opportunity for generic competition sooner than anticipated. Moreover, the extent to which a biosimilar, once approved, will be substituted for any one of the reference products in a way that is similar to traditional generic substitution for non-biological products is not yet clear, and will depend on a number of marketplace and regulatory factors that are still developing.

The FDA may disagree with our regulatory plan and we may fail to obtain regulatory approval of our product candidates.

If and when our ongoing Phase 2 clinical trials for ONA-XR and planned clinical trials for our other initial product candidates are completed and, assuming positive data, we expect to advance to potential registrational trials. The general approach for FDA approval of a new biologic or drug is for the sponsor to provide dispositive data from two well-controlled, Phase 3 clinical studies of the relevant biologic or drug in the relevant patient population. Phase 3 clinical studies typically involve hundreds of patients, have significant costs and take years to complete. If the results from our clinical trials are sufficiently compelling, we intend to discuss with the FDA submission of a BLA or NDA, as applicable for the relevant product candidate. However, we do not have any agreement or guidance from the FDA that our regulatory development plans will be sufficient for submission of a BLA or NDA, as applicable for the relevant product candidate. For example, the FDA may require that we conduct a comparative trial against an approved therapy, which would significantly delay our development timelines and require substantially more resources.

The FDA may grant accelerated approval for our product candidates and, as a condition for accelerated approval, the FDA may require a sponsor of a drug or biologic receiving accelerated approval to perform post-marketing studies to verify and describe the predicted effect on irreversible morbidity or mortality or other clinical endpoint, and the drug or biologic may be subject to withdrawal procedures by the FDA that are more accelerated than those available for regular approvals. We believe an accelerated approval strategy is warranted given the limited alternatives for patients that our initial product candidates target, but the FDA may ultimately require a Phase 3 clinical trial prior to approval, particularly since our product candidates represent a novel treatment. In addition, the standard of care may change with the approval of new products in the same indications that we are studying. This may result in the FDA or other regulatory agencies requesting additional studies to show that our product candidate is superior to the new products.

Our clinical trial results may also not support approval. In addition, our product candidates could fail to receive regulatory approval for many reasons, including the following:

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Obtaining and maintaining regulatory approval of our product candidates in one jurisdiction does not mean that we will be successful in obtaining regulatory approval of our product candidates in other jurisdictions.

Obtaining and maintaining regulatory approval of our product candidates in one jurisdiction does not guarantee that we will be able to obtain or maintain regulatory approval in any other jurisdiction, while a failure or delay in obtaining regulatory approval in one jurisdiction may have a negative effect on the regulatory approval process in others. For example, even if the FDA grants marketing approval of a product candidate, comparable regulatory authorities in foreign jurisdictions must also approve the manufacturing, marketing and promotion of the product candidate in those countries. Approval procedures vary among jurisdictions and can involve requirements and administrative review periods different from, and greater than, those in the United States, including additional preclinical studies or clinical trials as clinical studies conducted in one jurisdiction may not be accepted by regulatory authorities in other jurisdictions. In many jurisdictions outside the United States, a product candidate must be approved for reimbursement before it can be approved for sale in that jurisdiction. In some cases, the price that we intend to charge for our products is also subject to approval.

We may also submit marketing applications in other countries. Regulatory authorities in jurisdictions outside of the United States have requirements for approval of product candidates with which we must comply prior to marketing in those jurisdictions. Obtaining foreign regulatory approvals and compliance with foreign regulatory requirements could result in significant delays, difficulties and costs for us and could delay or prevent the introduction of our products in certain countries. If we fail to comply with the regulatory requirements in international markets and/or receive applicable marketing approvals, our target market will be reduced and our ability to realize the full market potential of our product candidates will be harmed.

We will be subject to ongoing regulatory obligations and continued regulatory review, which may result in significant additional expense and we may be subject to penalties if we fail to comply with regulatory requirements or experience unanticipated problems with our product candidates.

Any regulatory approvals that we receive for our product candidates will require surveillance to monitor the safety and efficacy of the product candidate. The FDA may also require a Risk Evaluation and Mitigation Strategy (“REMS”) in order to approve our product candidates, which could entail requirements for a medication guide, physician communication plans or additional elements to ensure safe use, such as restricted distribution methods, patient registries and other risk minimization tools. In addition, if the FDA or a comparable foreign regulatory authority approves our product candidates, the manufacturing processes, labeling, packaging, distribution, adverse event reporting, storage, advertising, promotion, import, export and recordkeeping for our product candidates will be subject to extensive and ongoing regulatory requirements. These requirements include submissions of safety and other post-marketing information and reports, registration, as well as continued compliance with cGMPs and GCPs for any clinical trials that we conduct post-approval. As such, we and our contract manufacturers will be subject to continual review and inspections to assess compliance with cGMP and

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adherence to commitments made in any BLA, other marketing application and previous responses to inspectional observations. Accordingly, we and others with whom we work must continue to expend time, money and effort in all areas of regulatory compliance, including manufacturing, production and quality control. In addition, the FDA could require us to conduct another study to obtain additional safety or biomarker information. Further, we will be required to comply with FDA promotion and advertising rules, which include, among others, standards for direct-to-consumer advertising, restrictions on promoting products for uses or in patient populations that are not described in the product’s approved uses (known as “off-label use”), limitations on industry-sponsored scientific and educational activities and requirements for promotional activities involving the internet and social media. Later discovery of previously unknown problems with our product candidates, including adverse events of unanticipated severity or frequency, or with our third-party suppliers or manufacturing processes, or failure to comply with regulatory requirements, may result in revisions to the approved labeling to add new safety information; imposition of post-market studies or clinical studies to assess new safety risks; or imposition of distribution restrictions or other restrictions under a risk evaluation and mitigation strategy program. Other potential consequences include, among other things:

The FDA’s and other regulatory authorities’ policies may change and additional government regulations may be enacted that could prevent, limit or delay regulatory approval of our product candidates. We cannot predict the likelihood, nature or extent of government regulation that may arise from future legislation or administrative or executive action, either in the United States or abroad. If we are slow or unable to adapt to changes in existing requirements or the adoption of new requirements or policies, or if we are not able to maintain regulatory compliance, we may lose any marketing approval that we may have obtained and we may not achieve or sustain profitability.

Even if we obtain regulatory approval of our product candidates, the products may not gain market acceptance among physicians, patients, hospitals, cancer treatment centers and others in the medical community.

The use of progesterone receptor and protein inhibitors as potential cancer treatments are recent developments and may not become broadly accepted by physicians, patients, hospitals, cancer treatment centers and others in the medical community and we may not be able to convince them to use our product candidates for many reasons. Additional factors will influence whether our product candidates are accepted in the market, including:

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If our product candidates are approved but fail to achieve market acceptance among physicians, patients, hospitals, cancer treatment centers or others in the medical community, we will not be able to generate significant revenue. Even if our products achieve market acceptance, we may not be able to maintain that market acceptance over time if new products or technologies are introduced that are more favorably received than our products, are more cost effective or render our products obsolete.

Coverage and reimbursement may be limited or unavailable in certain market segments for our product candidates, which could make it difficult for us to sell our product candidates, if approved, profitably.

Successful sales of our product candidates, if approved, depend on the availability of coverage and adequate reimbursement from third-party payors including governmental healthcare programs, such as Medicare and Medicaid, managed care organizations and commercial payors, among others. Significant uncertainty exists as to the coverage and reimbursement status of any product candidates for which we obtain regulatory approval. In addition, because our product candidates represent new approaches to the treatment of cancer, we cannot accurately estimate the potential revenue from our product candidates.

Patients who are provided medical treatment for their conditions generally rely on third-party payors to reimburse all or part of the costs associated with their treatment. Obtaining coverage and adequate reimbursement from third-party payors is critical to new product acceptance.

Third-party payors decide which drugs and treatments they will cover and the amount of reimbursement. Reimbursement by a third-party payor may depend upon a number of factors, including, but not limited to, the third-party payor’s determination that use of a product is:

Obtaining coverage and reimbursement of a product from a government or other third-party payor is a time-consuming and costly process that could require us to provide to the payor supporting scientific, clinical and cost-effectiveness data for the use of our products. Even if we obtain coverage for a given product, if the resulting reimbursement rates are insufficient, hospitals may not approve our product for use in their facility or third-party payors may require co-payments that patients find unacceptably high. Patients are unlikely to use our product candidates unless coverage is provided and reimbursement is adequate to cover a significant portion of the cost of our product candidates. Separate reimbursement for the product itself may or may not be available. Instead, the hospital or administering physician may be reimbursed only for providing the treatment or procedure in which our product is used. Further, from time to time, the Centers for Medicare & Medicaid Services, or the CMS, revises the reimbursement systems used to reimburse health care providers, including the Medicare Physician Fee Schedule and Outpatient Prospective Payment System, which may result in reduced Medicare payments. In some cases, private third-party payers rely on all or portions of Medicare payment systems to determine payment rates. Changes to government healthcare programs that reduce payments under these programs may negatively impact payments from private third-party payers, and reduce the willingness of physicians to use our product candidates.

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In the United States, no uniform policy of coverage and reimbursement for products exists among third-party payors. Therefore, coverage and reimbursement for products can differ significantly from payor to payor. Further, one payor’s determination to provide coverage for a product does not assure that other payors will also provide coverage for the product. Adequate third-party reimbursement may not be available to enable us to maintain price levels sufficient to realize an appropriate return on our investment in product development.

We intend to seek approval to market our product candidates in both the United States and in selected foreign jurisdictions. If we obtain approval in one or more foreign jurisdictions for our product candidates, we will be subject to rules and regulations in those jurisdictions. In some foreign countries, particularly those in Europe, the pricing of drugs and biologics is subject to governmental control. In these countries, pricing negotiations with governmental authorities can take considerable time after obtaining marketing approval of a product candidate. Some of these countries may require the completion of clinical trials that compare the cost-effectiveness of a particular product candidate to currently available therapies. Other member states allow companies to fix their own prices for medicines, but monitor and control company profits. The downward pressure on health care costs has become very intense. As a result, increasingly high barriers are being erected to the entry of new products. In addition, in some countries, cross-border imports from low-priced markets exert a commercial pressure on pricing within a country.

The marketability of any product candidates for which we receive regulatory approval for commercial sale may suffer if government and other third-party payors fail to provide coverage and adequate reimbursement. We expect downward pressure on pharmaceutical pricing to continue. Further, coverage policies and third-party reimbursement rates may change at any time. Even if favorable coverage and reimbursement status is attained for one or more products for which we receive regulatory approval, less favorable coverage policies and reimbursement rates may be implemented in the future.

The advancement of healthcare reform may negatively impact our ability to sell our product candidates, if approved, profitably.

In the United States and other jurisdictions, there have been, and we expect there will continue to be, a number of legislative and regulatory changes and proposed changes to the healthcare system that could affect our future results of operations. In particular, there have been and continue to be a number of initiatives at the U.S. federal and state levels that seek to reduce healthcare costs and improve the quality of healthcare. For example, in March 2010, the Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act, or collectively the ACA, was enacted, which substantially changed the way healthcare is financed by both governmental and private payors. Among the provisions of the ACA of importance to the pharmaceutical and biotechnology industries, which includes biologics, are the following:

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Since its enactment, there have been judicial and Congressional challenges to certain aspects of the ACA, and we expect there will be additional challenges and amendments to the ACA in the future. For example, legislation enacted in 2017 informally titled the Tax Cuts and Jobs Act of 2017, repealed the tax-based shared responsibility payment imposed by the ACA on certain individuals who fail to maintain qualifying health coverage that is commonly referred to as the “individual mandate.” In December 2019, a U.S. District Court upheld a ruling that the ACA is unconstitutional in its entirety because the “individual mandate” was repealed by Congress. In November 2020, the Supreme Court of the United States heard oral arguments in the appeal of this case, but it is uncertain when the Supreme Court will rule on this case. It is unclear how this and other efforts to challenge, repeal, or replace the ACA will impact the ACA or our business.

In addition, other legislative changes have been proposed and adopted in the United States since the ACA was enacted which, among other things, have reduced Medicare payments to several types of providers, including hospitals and cancer treatment centers.

These new laws or any other similar laws introduced in the future, as well as regulatory actions that may be taken by CMS, may result in additional reductions in Medicare and other healthcare funding, which could negatively affect our customers and accordingly, our financial operations. Moreover, payment methodologies may be subject to changes in healthcare legislation and regulatory initiatives. Additionally, individual states in the United States have passed legislation and implemented regulations designed to control pharmaceutical and biological product pricing and costs. Similar developments have occurred outside of the United States, including in the European Union where healthcare budgetary constraints have resulted in restrictions on the pricing and reimbursement of medicines by relevant health service providers.

To obtain reimbursement or pricing approval in some European Union member states, we may be required to conduct studies that compare the cost-effectiveness of our product candidates to other therapies that are considered the local standard of care. It is also possible that additional governmental action is taken in response to address the COVID-19 pandemic. We cannot predict the likelihood, nature, or extent of government regulation that may arise from future legislation or administrative action in the United States, particularly as a result of the recent presidential election, or any other jurisdiction. If we or any third parties we may engage are slow or unable to adapt to changes in existing requirements or the adoption of new requirements or policies, or if we or such third parties are not able to maintain regulatory compliance, our product candidates may lose any regulatory approval that may have been obtained and we may not achieve or sustain profitability.

Risks Related to Intellectual Property

Patents and patent applications involve highly complex legal and factual questions, which, if determined adversely to us, could negatively impact our business position.

The patent positions of biopharmaceutical companies and other actors in our fields of business can be highly uncertain and typically involve complex scientific, legal and factual analyses. In particular, the interpretation and breadth of claims allowed in some patents covering biopharmaceutical compositions may be uncertain and

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difficult to determine, and are often affected materially by the facts and circumstances that pertain to the patented compositions and the related patent claims. The standards of the United States Patent and Trademark Office (the USPTO) and its foreign counterparts are sometimes uncertain and could change in the future.

Consequently, the issuance and scope of patents cannot be predicted with certainty. Patents, if issued, may be challenged, invalidated or designed around. U.S. patents and patent applications may also be subject to interference or derivation proceedings, and U.S. patents may be subject to reexamination, post-grant review and/or inter parties review proceedings in the USPTO.

International patents may also be subject to opposition or comparable proceedings in the corresponding international patent office, which could result in either loss of the patent or denial of the patent application, or loss or reduction in the scope of one or more of the claims of the patent or patent application. In addition, such interference, derivation, reexamination, post-grant review, inter parties review and opposition proceedings may be costly. Accordingly, rights under any issued patents may not provide us with sufficient protection against competitive products or processes.

Furthermore, even if not challenged, our patents and patent applications may not adequately protect our technology and any product candidates or products that we develop alone or with collaborators or prevent others from designing their products to avoid being covered by our claims. If the breadth or strength of protection provided by the patents and patent applications that we hold with respect to our product candidates or potential products is threatened, it could dissuade companies from collaborating with us to develop, and could threaten our or their ability to successfully commercialize, such product candidates or potential products.

In addition, changes in, or different interpretations of, patent laws in the United States and other countries may permit others to use our discoveries or to develop and commercialize our technology and product candidates or products without providing any compensation to us, or may limit the scope of patent protection that we are able to obtain. The laws of some countries do not protect intellectual property rights to the same extent as U.S. laws, and those countries may lack adequate rules and procedures for defending our intellectual property rights.

Periodic maintenance fees, renewal fees, annuity fees and various other governmental fees on patents and/or applications will be due to be paid to the USPTO and various governmental patent agencies outside of the United States in several stages over the lifetime of the patents and/or applications. We rely on our outside counsel and employ an outside firm to pay these fees due to USPTO and non-US patent agencies. The USPTO and various non-US governmental patent agencies require compliance with a number of procedural, documentary, fee payment and other similar provisions during the patent application process. Although an inadvertent lapse can be cured by payment of a late fee or by other means in accordance with the applicable rules, there are situations in which non-compliance can result in abandonment or lapse of the patent or patent application, resulting in partial or complete loss of patent rights in the relevant jurisdiction. In such an event, our competitors might be able to enter the market which would have a material adverse effect on our business.

If the patent applications we hold or have in-licensed with respect to our current and future research and development programs and product candidates fail to issue, if their validity, breadth or strength of protection is threatened, or if they fail to provide meaningful exclusivity for our technology or any products and product candidates that we or our collaborators may develop, it could dissuade companies from collaborating with us to develop product candidates, encourage competitors to develop competing products or technologies and threaten our or our collaborators’ ability to commercialize future product candidates. Any such outcome could have a material adverse effect on our business.

Our ability to compete effectively in our markets may decline if we do not adequately protect our proprietary rights, and our proprietary rights do not necessarily address all potential threats to our competitive advantages.

We rely on patent protection as well as trademark, trade secret and other intellectual property rights protection and contractual restrictions to protect ONA-XR, CLDN6xCD3 bsAb and other product candidates. Our commercial success depends upon obtaining and maintaining proprietary rights to our intellectual property

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estate, including rights relating to ONA-XR, CLDN6xCD3 bsAb and other product candidates, as well as successfully defending these rights against third-party challenges and successfully enforcing these rights to prevent third-party infringement. We will only be able to protect ONA-XR, CLDN6xCD3 bsAb and other product candidates from unauthorized use by third parties to the extent that valid and enforceable patents or effectively protected trade secrets cover them.

Our ability to obtain and maintain patent protection for ONA-XR, CLDN6xCD3 bsAb and other product candidates is uncertain due to a number of factors, including the following factors:

Even if we have or obtain patents covering ONA-XR, CLDN6xCD3 bsAb or any other product candidates or compositions, others may have filed, and in the future may file, patent applications covering compositions, products or methods that are similar or identical to ours, which could materially affect our ability to successfully develop any product candidates or to successfully commercialize any approved products alone or with collaborators. In addition, because patent applications can take many years to issue, there may be currently

pending applications unknown to us that may later result in issued patents that may cover ONA-XR, CLDN6xCD3 bsAb or any other product candidates or compositions. These patent applications may have priority over patent applications filed by us.

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The issuance of a patent is not conclusive as to its inventorship, scope, validity or enforceability, and our owned and licensed patents may be challenged in the courts or patent offices in the United States and abroad. Such challenges may result in loss of exclusivity or freedom to operate or in patent claims being narrowed, invalidated or held unenforceable, in whole or in part, which could limit our ability to stop others from using or commercializing similar or identical technology and products, or limit the duration of the patent protection of our technology and products.

In the United States, the natural expiration of a patent is generally 20 years after it is filed. Various extensions may be available; however the life of a patent, and the protection it affords, is limited.

Without patent protection for current or future product candidates, we may be open to competition from generic or biosimilar versions of such potential products. Given the amount of time required for the development, testing and regulatory review of new product candidates, patents protecting such candidates might expire before or shortly after such candidates are commercialized. As a result, our owned and licensed patent portfolio may not provide us with sufficient rights to exclude others from commercializing products similar or identical to those we or our collaborators may develop.

In addition, we also try to protect our trade secrets, know-how and other proprietary information through non-disclosure and confidentiality provisions in our agreements with parties who have access to them, such as our employees, consultants and research partners. Such agreements may not be enforceable or may not provide meaningful protection for our trade secrets, know-how and/or other proprietary information in the event of unauthorized uses or disclosure or other breaches of the provisions, and we may not be able to prevent such unauthorized uses or disclosure. Moreover, if a party having an agreement with us has an overlapping or conflicting obligation to a third party, our rights in and to certain intellectual property could be undermined. Monitoring unauthorized and inadvertent disclosure and uses is difficult, and we do not know whether the steps we have taken to prevent such disclosure and uses are, or will be, adequate. In addition, monitoring unauthorized disclosure and uses of our trade secrets is difficult, and we do not know whether the steps we have taken to prevent such disclosure and uses are, or will be, adequate. If we were to enforce a claim that a third-party had illegally obtained and was using our trade secrets, it would be expensive and time-consuming, and the outcome would be unpredictable, and any remedy may be inadequate. In addition, courts outside the United States may be less willing to protect trade secrets.

We rely on trade secrets to protect our proprietary technologies, especially where we do not believe patent protection is appropriate or obtainable. However, trade secrets are difficult to protect. We rely in part on confidentiality agreements with our employees, consultants, outside scientific collaborators, sponsored researchers and other advisors to protect our trade secrets and other proprietary information. These agreements may not effectively prevent disclosure of confidential information and may not provide an adequate remedy in the event of unauthorized disclosure of confidential information. In addition, others may independently discover our trade secrets and proprietary information. Costly and time-consuming litigation could be necessary to enforce and determine the scope of our proprietary rights, and failure to obtain or maintain trade secret protection could adversely affect our competitive business position.

Because we may rely on third parties to manufacture our potential product candidates, and because we collaborate with various organizations and academic institutions on the advancement of our current and potential product candidates, we must, at times, share trade secrets with them. We seek to protect our proprietary technology in part by entering into confidentiality agreements and, if applicable, material transfer agreements, collaborative research agreements, consulting agreements or other similar agreements with our manufacturers, collaborators, advisors, employees and consultants prior to beginning research or disclosing proprietary information. These agreements typically limit the rights of the third parties to use or disclose our confidential information, such as trade secrets. Despite the contractual provisions employed when working with third parties, the need to share trade secrets and other confidential information increases the risk that such trade secrets become known by our competitors, are inadvertently incorporated into the technology of others, are used

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inappropriately to create new inventions or are disclosed or used in violation of these agreements. Given that our proprietary position is based, in part, on our know-how and trade secrets, a competitor’s discovery of our trade secrets or other unauthorized use or disclosure would impair our competitive position and may have a material adverse effect on our business.

If we fail to comply with our obligations in the agreements under which we license intellectual property rights from third parties or otherwise experience disruptions to our business relationships with our licensors, we could lose license rights that are important to our business.

We are a party to intellectual property license agreements that are important to our business and expect to enter into additional license agreements in the future. Our existing license agreements impose, and we expect that future license agreements will impose, various diligence, milestone payment, royalty and other obligations on us. Additionally, we may need to outsource and rely on third parties for many aspects of the development, sales and marketing of any products covered under our current and future license agreements. Delay or failure by these third parties could adversely affect the continuation of our license agreements with our licensors. If we fail to comply with any of our obligations under these agreements, or we are subject to a bankruptcy, our licensors may have the right to terminate the license, in which event we would not be able to market any products covered by the license.

In some cases, patent prosecution of our licensed technology is controlled solely by the licensor. If such licensor fails to obtain and maintain patent or other protection for the proprietary intellectual property we license from such licensor, we could lose our rights to such intellectual property or the exclusivity of such rights, and our competitors could market competing products using such intellectual property. In that event, we may be required to expend significant time and resources to develop or license replacement technology.

If we are unable to do so, we or our collaborators may be unable to develop or commercialize the affected product candidates, which could harm our business significantly. In other cases, we control the prosecution of patents resulting from licensed technology. In the event we breach any of our obligations related to such prosecution, we may incur significant liability to our licensing partners.

Licensing of intellectual property is of critical importance to our business and involves complex legal, business and scientific issues and is complicated by the rapid pace of scientific discovery in our industry. Disputes may arise regarding intellectual property subject to a licensing agreement, including:

If disputes over intellectual property that we have licensed prevent or impair our ability to maintain our current licensing arrangements on acceptable terms, we may be unable to successfully develop and commercialize the affected product candidates.

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If we do not obtain patent term extension in the United States under the Hatch-Waxman Act and in foreign countries under similar legislation with respect to our product candidates, thereby potentially extending the term of marketing exclusivity for such product candidates, our business may be harmed.

In the United States, a patent that covers an FDA-approved drug or biologic may be eligible for a term extension designed to restore the period of the patent term that is lost during the premarket regulatory review process conducted by the FDA. Depending upon the timing, duration and conditions of FDA marketing approval of our product candidates, one or more of our U.S. patents may be eligible for limited patent term extension under the Drug Price Competition and Patent Term Restoration Act of 1984, or the Hatch-Waxman Act, which permits a patent term extension of up to five years for a patent covering an approved product as compensation for effective patent term lost during product development and the FDA regulatory review process.

In the European Union, our product candidates may be eligible for term extensions based on similar legislation. In either jurisdiction, however, we may not receive an extension if we fail to apply within applicable deadlines, fail to apply prior to expiration of relevant patents or otherwise fail to satisfy applicable requirements.

Even if we are granted such extension, the duration of such extension may be less than our request. If we are unable to obtain a patent term extension, or if the term of any such extension is less than our request, the period during which we can enforce our patent rights for that product will be in effect shortened and our competitors may obtain approval to market competing products sooner. The resulting reduction of years of revenue from applicable products could be substantial.

We may not be able to protect our intellectual property rights throughout the world.

Filing, prosecuting and defending patents on product candidates in all countries throughout the world would be prohibitively expensive, and our intellectual property rights in some countries outside the United States can be less extensive than those in the United States. In addition, the laws of some foreign countries do not protect intellectual property rights to the same extent as federal and state laws in the United States. Consequently, we may not be able to prevent third parties from practicing our inventions in all countries outside the United States, or from selling or importing products made using our inventions in and into the United States or other jurisdictions. Competitors may use our technologies in jurisdictions where we have not obtained patent protection to develop their own products and further, may export otherwise infringing products to territories where we have patent protection, but enforcement is not as strong as that in the United States. These products may compete with our products and our patents or other intellectual property rights may not be effective or sufficient to prevent them from competing.

Many companies have encountered significant problems in protecting and defending intellectual property rights in foreign jurisdictions. The legal systems of certain countries, particularly certain developing countries, do not favor the enforcement of patents, trade secrets and other intellectual property protection, particularly those relating to biotechnology products, which could make it difficult for us to stop the infringement of our patents or marketing of competing products in violation of our proprietary rights generally. Proceedings to enforce our patent rights in foreign jurisdictions could result in substantial costs and divert our efforts and attention from other aspects of our business, could put our patents at risk of being invalidated or interpreted narrowly and our patent applications at risk of not issuing and could provoke third parties to assert claims against us. We may not prevail in any lawsuits that we initiate, and the damages or other remedies awarded, if any, may not be commercially meaningful. Accordingly, our efforts to enforce our intellectual property rights around the world may be inadequate to obtain a significant commercial advantage from the intellectual property that we develop or license.

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Third parties may assert claims against us alleging infringement of their patents and proprietary rights, or we may need to become involved in lawsuits to defend or enforce our patents, either of which could result in substantial costs or loss of productivity, delay or prevent the development and commercialization of product candidates, prohibit our use of proprietary technology or sale of potential products or put our patents and other proprietary rights at risk.

Our commercial success depends in part upon our ability to develop, manufacture, market and sell product candidates without alleged or actual infringement, misappropriation or other violation of the patents and proprietary rights of third parties. Litigation relating to infringement or misappropriation of patent and other intellectual property rights in the pharmaceutical, biotechnology is common, including patent infringement lawsuits, and such interference, derivation, reexamination, post-grant review, inter parties review and opposition proceedings before the USPTO and corresponding international patent offices.

The various markets in which we plan to operate are subject to frequent and extensive litigation regarding patents and other intellectual property rights. In addition, many companies in intellectual property-dependent industries, including the biotechnology and pharmaceutical industries, have employed intellectual property litigation as a means to gain an advantage over their competitors.

Numerous United States, EU and other internationally issued patents and pending patent applications, which are owned by third parties, exist in the fields in which we and our collaborators are developing product candidates, and as the biotechnology and pharmaceutical industries expand and more patents are issued, the risk increases that our product candidates may be subject to claims of infringement of the intellectual property rights of third parties.

As a result of any patent infringement claims, or in order to avoid any potential infringement claims, we may choose to seek, or be required to seek, a license from a third party, which may require payment of substantial royalties or fees, or require us to grant a cross-license under our intellectual property rights.

These licenses may not be available on reasonable terms or at all. Even if a license can be obtained on reasonable terms, the rights may be nonexclusive, which would give our competitors access to the same intellectual property rights. If we are unable to enter into a license on acceptable terms, we or our collaborators could be prevented from commercializing one or more product candidates, or forced to modify such product candidates, or to cease some aspect of our business operations, which could harm our business significantly.

We or our collaborators might also be forced to redesign or modify our technology or product candidates so that we no longer infringe the third-party intellectual property rights, which may result in significant cost or delay to us, or which redesign or modification could be impossible or technically infeasible. Even if we were ultimately to prevail, any of these events could require us to divert substantial financial and management resources that we would otherwise be able to devote to our business.

Further, if a patent infringement suit is brought against us, our collaborators or our third-party service providers, our development, manufacturing or sales activities relating to the product or product candidate that is the subject of the suit may be delayed or terminated. In addition, defending such claims has in the past and may in the future cause us to incur substantial expenses and, if successful, could cause us to pay substantial damages if we are found to be infringing a third party’s patent rights.

These damages potentially include increased damages and attorneys’ fees if we are found to have infringed such rights willfully. Some claimants may have substantially greater resources than we do and may be able to sustain the costs of complex intellectual property litigation to a greater degree and for longer periods of time than we could. In addition, patent holding companies that focus solely on extracting royalties and settlements by enforcing patent rights may target us.

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We may in the future be subject to third-party claims and similar adversarial proceedings or litigation in other jurisdictions regarding our infringement of the patent rights of third parties. Even if such claims are without merit, a court of competent jurisdiction could hold that these third-party patents are valid, enforceable and infringed, and the holders of any such patents may be able to block our or our collaborators’ ability to further develop or commercialize the applicable product candidate unless we obtain a license under the applicable patents, or until such patents expire or are finally determined to be invalid or unenforceable.

Similarly, if any third-party patents were held by a court of competent jurisdiction to cover aspects of our technologies, compositions, formulations, or methods of treatment, prevention or use, the holders of any such patents may be able to prohibit our use of those technologies, compositions, formulations, methods of treatment, prevention or use or other technologies, effectively blocking our or our collaborators’ ability to develop and commercialize the applicable product candidate until such patent expires or is finally determined to be invalid or unenforceable or unless we or our collaborators obtain a license.

Competitors may infringe our patents. In the event of infringement or unauthorized use, we may file one or more infringement lawsuits, which can be expensive and time-consuming. An adverse result in any such litigation proceedings could put one or more of our patents at risk of being invalidated, being found to be unenforceable, and/or being interpreted narrowly and could put our patent applications at risk of not issuing and/or could impact the validity or enforceability positions of our other patents. Furthermore, because of the substantial amount of discovery required in connection with intellectual property litigation, there is a risk that some of our confidential information could be compromised by disclosure during this type of litigation.

Some of our competitors may be able to sustain the costs of complex intellectual property litigation more effectively than we can because they have substantially greater resources. In addition, intellectual property litigation, regardless of its outcome, may cause negative publicity, adversely impact prospective customers, cause product shipment delays or prohibit us from manufacturing, marketing or otherwise commercializing our products, services and technology.

Any uncertainties resulting from the initiation and continuation of any litigation could have a material adverse effect on our ability to raise additional funds or otherwise have a material adverse effect on our business, results of operation, financial condition or cash flows.

Changes in U.S. patent law could diminish the value of patents in general, thereby impairing our ability to protect our products.

The United States has enacted and is currently implementing wide-ranging patent reform legislation. Recent U.S. Supreme Court rulings have narrowed the scope of patent protection available in certain circumstances and weakened the rights of patent owners in certain situations. In addition to increasing uncertainty with regard to our ability to obtain patents in the future, this combination of events has created uncertainty with respect to the value of patents, once obtained. Depending on decisions by the U.S. Congress, the federal courts and the USPTO, the laws and regulations governing patents could change in unpredictable ways that would weaken our ability to obtain new patents or to enforce our existing patents and patents that we might obtain in the future.

Risks Related to this Offering and the Market for Our Common Stock

No active trading market for our common stock currently exists, and an active trading market may not develop.

Prior to this offering, there has not been an active trading market for our common stock. If an active trading market for our common stock does not develop following this offering, you may not be able to sell your shares quickly or at the market price. Our ability to raise capital to continue to fund operations by selling shares of our common stock and our ability to acquire other companies or technologies by using shares of our common stock as consideration may also be impaired. The initial public offering price of our common stock will be determined by negotiations between us and the underwriter and may not be indicative of the market prices of our common stock that will prevail in the trading market.

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Our common stock may be volatile or may decline regardless of our operating performance, and you may not be able to resell your shares at or above the initial public offering price.

After this offering, the market price for our common stock is likely to be volatile, in part because our shares have not been traded publicly. In addition, the market price of our common stock may fluctuate significantly in response to several factors, most of which we cannot control, including:

The public offering price of our common stock has been determined by us based upon many factors and may not be indicative of prices that will prevail following the closing of this offering. Volatility in the market price of our common stock may prevent investors from being able to sell their shares at or above the initial public offering price. As a result, you may suffer a loss on your investment.

If securities or industry analysts do not publish research or publish inaccurate or unfavorable research about our business, the market price for the shares and trading volume could decline.

The trading market for our common stock will depend in part on the research and reports that securities or industry analysts publish about us or our business. If research analysts do not establish and maintain adequate research coverage or if one or more of the analysts who covers us downgrades our common stock or publishes inaccurate or unfavorable research about our business, the market price for our common stock would likely decline. If one or more of these analysts cease coverage of our company or fail to publish reports on us regularly, we could lose visibility in the financial markets, which, in turn, could cause the market price or trading volume for our common stock to decline.

As our initial public offering price is substantially higher than our net tangible book value per share, you will experience immediate and substantial dilution.

If you purchase shares in this offering, you will pay more for your shares of common stock than the amount paid by our existing stockholders for their shares on a per share basis. As a result, you will experience immediate and substantial dilution in net tangible book value per share in relation to the price that you paid for your shares. We expect the dilution as a result of the offering to be $             per share to new investors purchasing our shares in this offering. In addition, you will experience further dilution to the extent that our shares are issued upon the exercise of any warrants or exercise of stock options under any stock incentive plans. See “Dilution” for a more complete description of how the value of your investment in our shares will be diluted upon completion of this offering.

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We have considerable discretion as to the use of the net proceeds from this offering and we may use these proceeds in ways with which you may not agree. We will require additional capital to fund our operations, and if we fail to obtain necessary financing, we may not be able to advance or complete the development and commercialization of our product candidates.

We intend to use the proceeds from this offering primarily to fund the development of ONA-XR, including our three ongoing Phase 2 trials, our ongoing Phase 1b/2 trial and two ongoing Phase 0 trials, as well as CLDN6xCD3 bsAb and the remaining amounts to fund the development of other research and development activities as well as for working capital and general corporate purposes. However, we have considerable discretion in the application of the proceeds. You will not have the opportunity, as part of your investment decision, to assess whether the proceeds are being used appropriately. You must rely on the judgment of our management regarding the application of the net proceeds of this offering. The net proceeds may be used for corporate or other purposes with which you do not agree or that do not improve our profitability or increase our share price. The net proceeds from this offering may also be placed in investments that do not produce income or that lose value.

Our future funding requirements, both near and long-term, will depend on many factors, including, but not limited to:

If we are unable to expand our operations or otherwise capitalize on our business opportunities due to a lack of capital, our ability to become profitable will be compromised.

After this offering, our directors, executive officers and certain stockholders will continue to own a significant percentage of our common stock and, if they choose to act together, will be able to exert significant control over matters subject to stockholder approval.

Upon the closing of this offering, our directors, executive officers, and stockholders affiliated with our directors and executive officers will beneficially own approximately            % of the voting power of our outstanding common stock, or approximately            % if the underwriter exercises its over-allotment option from us in full. Therefore, they will have the ability to substantially influence us through their ownership position. For example, these holders may be able to control elections of directors, amendments of our organizational documents, or approval of any merger, sale of assets, or other major corporate transaction. The interests of these

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holders may not always coincide with our corporate interests or the interests of other stockholders, and they may act in a manner with which you may not agree or that may not be in the best interests of our other stockholders. So long as they continue to own a significant amount of our equity, these holders will be able to strongly influence or effectively control our decisions.

We do not expect to pay dividends in the foreseeable future after this offering, and you must rely on price appreciation of your shares for return on your investment.

We have paid no cash dividends on any class of our stock to date and we do not anticipate paying cash dividends in the near term. For the foreseeable future, we intend to retain any earnings to finance the development and expansion of our business, and we do not anticipate paying any cash dividends on our stock. Accordingly, investors must be prepared to rely on sales of their shares after price appreciation to earn an investment return, which may never occur. Investors seeking cash dividends should not purchase our shares. Any determination to pay dividends in the future will be made at the discretion of our board of directors and will depend on our results of operations, financial condition, contractual restrictions, restrictions imposed by applicable law and other factors our board deems relevant.

We may issue additional debt and equity securities, which are senior to our common stock as to distributions and in liquidation, which could materially adversely affect the market price of our common stock.

In the future, we may attempt to increase our capital resources by entering into additional debt or debt-like financing that is secured by all or up to all of our assets, or issuing debt or equity securities, which could include issuances of commercial paper, medium-term notes, senior notes, subordinated notes or shares. In the event of our liquidation, our lenders and holders of our debt securities would receive a distribution of our available assets before distributions to our stockholders. In addition, any additional preferred stock, if issued by our company, may have a preference with respect to distributions and upon liquidation, which could further limit our ability to make distributions to our stockholders. Because our decision to incur debt and issue securities in our future offerings will depend on market conditions and other factors beyond our control, we cannot predict or estimate the amount, timing or nature of our future offerings and debt financing.

Further, market conditions could require us to accept less favorable terms for the issuance of our securities in the future. Thus, you will bear the risk of our future offerings reducing the value of your common stock and diluting your interest in our company.

We will be subject to ongoing public reporting requirements that are less rigorous than Exchange Act rules for companies that are not emerging growth companies and our stockholders could receive less information than they might expect to receive from more mature public companies.

Upon the completion of this offering, we will be required to publicly report on an ongoing basis as an “emerging growth company” (as defined in the JOBS Act) under the reporting rules set forth under the Exchange Act. For so long as we remain an emerging growth company, we may take advantage of certain exemptions from various reporting requirements that are applicable to other Exchange Act reporting companies that are not emerging growth companies, including but not limited to:

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In addition, Section 107 of the JOBS Act also provides that an emerging growth company can take advantage of the extended transition period provided in Section 7(a)(2)(B) of the Securities Act for complying with new or revised accounting standards. In other words, an emerging growth company can delay the adoption of certain accounting standards until those standards would otherwise apply to private companies. We have elected to take advantage of the benefits of this extended transition period. Our financial statements may therefore not be comparable to those of companies that comply with such new or revised accounting standards.

We expect to take advantage of these reporting exemptions until we are no longer an emerging growth company. We would remain an emerging growth company for up to five years from the date of the first sale of equity securities pursuant to an effective registration statement, although if the market value of our common stock that is held by non-affiliates exceeds $700 million as of any June 30 before that time, we would cease to be an emerging growth company as of the following December 31.

Because we will be subject to ongoing public reporting requirements that are less rigorous than Exchange Act rules for companies that are not emerging growth companies, our stockholders could receive less information than they might expect to receive from more mature public companies. We cannot predict if investors will find our common stock less attractive if we elect to rely on these exemptions, or if taking advantage of these exemptions would result in less active trading or more volatility in the price of our common stock.

We have material weaknesses in our internal control over financial reporting and will need to hire additional personnel and design and implement proper and effective internal control over financial reporting. We may identify additional material weaknesses in the future that may cause us to fail to meet our reporting obligations or result in material misstatements in our financial statements. If we fail to remediate our material weaknesses, we may not be able to report our financial results accurately or to prevent fraud.

Our management is responsible for establishing and maintaining internal control over financial reporting, disclosure controls, and compliance with the other requirements of the Sarbanes-Oxley Act and the rules promulgated by the SEC thereunder. Internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements in accordance with US GAAP. The PCAOB defines a material weakness as a deficiency, or combination of deficiencies, in internal control over financial reporting, such that there is a reasonable possibility that a material misstatement of annual or interim financial statements will not be prevented, or detected and corrected, on a timely basis.

During the preparation of our consolidated financial statements for the years ended December 31, 2019 and 2020, we and our independent registered public accounting identified a material weakness related to the lack of an appropriate review of the internally prepared financial statements which resulted in the Company’s failure to timely detect and correct certain misstatements within the consolidated financial statements. Such misstatements have been corrected in the accompanying consolidated financial statements for the years ended December 31, 2019 and 2020. We also identified a material weakness as it relates to a lack of adequate segregation of accounting functions.

Management will aim to remediate the material weaknesses described above through hiring additional qualified accounting and financial reporting personnel, and designing and implementing financial reporting systems, processes, policies and internal control. However, we will not be able to fully remediate these material weaknesses until these steps have been completed and are functioning effectively, which may expose us to errors, losses or fraud until remediated. In addition, we cannot at this time provide an estimate of the costs we expect to incur or the expected timeline in connection with implementing our remediation plan. These remediation measures may be time-consuming and costly, and might place significant demands on our financial and operational resources. If we are unable to successfully remediate these material weaknesses or successfully supervise and rely on outside advisors with expertise in these matters to assist us in the preparation of our financial statements, our financial statements could contain material misstatements that, when discovered in the future, could cause us to fail to meet our future reporting obligations and cause the price of our common stock to decline.

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Our independent registered public accounting firm has included an explanatory paragraph relating to our ability to continue as a going concern in its report on our audited consolidated financial statements for the year ended December 31, 2020 included in this prospectus.

The report from our independent registered public accounting firm for the year ended December 31, 2020 includes an explanatory paragraph stating that our recurring losses and negative cash flows from operations, working capital deficit and accumulated deficit raise substantial doubt about our ability to continue as a going concern. We will continue to seek to raise additional capital in the future through equity and/or debt financings, partnerships, collaborations, or other sources to carry out the Company’s planned development activities. If additional capital is not available when required, the Company may need to delay or curtail its operations until such funding is received. Future reports from our independent registered public accounting firm may also contain statements expressing substantial doubt about our ability to continue as a going concern.

Raising additional capital may cause dilution to our stockholders, including purchasers of common stock in this offering, restrict our operations or require us to relinquish rights to our technologies or product candidates.

Until such time, if ever, as we can generate substantial product revenues, we expect to finance our cash needs through a combination of equity and/or debt financings and collaborations, licensing agreements or other strategic arrangements. To the extent that we raise additional capital through the sale of equity or convertible debt securities, your ownership interest will be diluted, and the terms of such securities may include liquidation or other preferences that adversely affect your rights as a common stockholder.

To the extent that we raise additional capital through debt financing, it would result in increased fixed payment obligations and a portion of our operating cash flows, if any, being dedicated to the payment of principal and interest on such indebtedness. In addition, debt financing may involve agreements that include restrictive covenants that impose operating restrictions, such as restrictions on the incurrence of additional debt, the making of certain capital expenditures or the declaration of dividends.

To the extent we raise additional capital through arrangements with collaborators or otherwise, we may be required to relinquish some of our technologies, research programs, product development activities, product candidates and/or future revenue streams, license our technologies and/or product candidates on unfavorable terms or otherwise agree to terms unfavorable to us. Furthermore, any capital raising efforts may divert our management from their day-to-day activities, which may adversely affect our ability to advance research programs, product development activities or product candidates.

General Risk Factors

We will incur increased costs as a result of becoming a public company and in the administration of our organizational structure.

As a public company, we will incur significant legal, accounting, insurance, and other expenses that we have not incurred as a private company, including costs associated with public company reporting requirements. We also have incurred and will incur costs associated with the Sarbanes-Oxley Act and related rules implemented by SEC. Following the consummation of this offering, we will incur ongoing periodic expenses in connection with the administration of our organizational structure. The expenses incurred by public companies generally for reporting and corporate governance purposes have been increasing. We expect these rules and regulations to increase our legal and financial compliance costs and to make some activities more time-consuming and costly, although we are currently unable to estimate these costs with any significant degree of certainty. In estimating these costs however, we took into account expenses related to insurance, legal, accounting, and compliance activities, as well as other expenses not currently incurred. These laws and regulations could also make it more difficult or costly for us to obtain certain types of insurance, including director and officer liability insurance, and we may be forced to accept reduced policy limits and coverage or

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incur substantially higher costs to obtain the same or similar coverage. These laws and regulations could also make it more difficult for us to attract and retain qualified persons to serve on our board of directors, our board committees or as our executive officers. Furthermore, if we are unable to satisfy our obligations as a public company, we could be subject to delisting of our common stock, fines, sanctions and other regulatory action and potentially civil litigation.

We are subject to complex tax rules relating to our business, and any audits, investigations or tax proceedings could have a

material adverse effect on our business, results of operations and financial condition. We are subject to income and non-income taxes in the United States and Ireland, as well as the tax laws and regulations related to such matters. Tax accounting and compliance often involves complex issues, and judgment and interpretation is required in determining our provision for income taxes and other tax liabilities as well as the application of tax laws and regulations. We could become subject to income and non-income taxes in non-US jurisdictions other than Ireland as well. In addition, many jurisdictions have detailed transfer pricing rules, which require that all transactions with related parties be priced using arm’s length pricing principles within the meaning of such rules.

The application of such transfer pricing rules, as well as of withholding taxes, goods and services taxes, sales taxes and other taxes is not always clear and we may be subject to tax audits relating to such rules or taxes. We believe that our tax positions are reasonable, and our tax provisions and reserves are adequate to cover any potential liability. We are also currently not subject to any tax audits.

However, various items cannot be accurately forecasted and future events may be treated as discrete to the period in which they occur. In addition, the Internal Revenue Service or other taxing authorities may disagree with our positions. In addition, existing tax laws, statutes, rules, regulations or ordinances could be interpreted, changed, modified or applied adversely to us (possibly with retroactive effect). If the Internal Revenue Service or any other tax authorities were successful in challenging our positions, or existing tax laws, statutes, rules, regulations or ordinances are so interpreted, changed or modified, we may be liable for additional tax and

penalties and interest related thereto or other taxes, as applicable, in excess of any reserves established therefor, which may have a significant impact on our results and operations and future cash flow.

Our business and operations would suffer in the event of system failures or security breaches.

Despite the implementation of security measures, our computer systems, as well as those of third parties with which we have relationships, are vulnerable to damage from computer viruses, unauthorized access, natural and manmade disasters, terrorism, war and telecommunication and electrical failures. If we or a third party with which we have relationships were to experience a system failure, accident or security breach such an event could cause interruptions in our or their operations, or it could result in delays and/or material disruptions of our research and development programs. For example, the loss of trial data from completed, ongoing or planned trials could result in delays in our regulatory approval efforts and significantly increase our costs to recover or reproduce the data. To the extent that any disruption or security breach were to result in a loss of or damage to data or applications, or inappropriate disclosure of personal, confidential or proprietary information, we could incur liability and the development of our product candidates could be delayed.

The U.S. federal and various state and foreign governments have enacted or proposed requirements regarding the collection, distribution, use, security and storage of personally identifiable information and other data relating to individuals, and U.S. federal and state consumer protection laws are being applied to enforce regulations related to the online collection, use and dissemination of data. In the ordinary course of our business, we and third parties with which we have relationships collect and store sensitive data, including intellectual property, clinical trial data, proprietary business information, personal data and personally identifiable information of our clinical trial subjects and employees, consultants and contractors, in data centers and on networks. The secure processing, maintenance and transmission of this information is critical to our operations. Despite our and our collaborators’ security measures, our information technology and infrastructure may be

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vulnerable to attacks by hackers or internal bad actors, breaches due to employee error, technical vulnerabilities, malfeasance or other disruptions, and any such breach could compromise our or their networks and the information stored there could be accessed, publicly disclosed, lost or stolen.

Any such access, disclosure, notifications, follow-up actions related to such a security breach or other loss of information could result in legal claims or proceedings, liability under laws that protect the privacy of personal information and significant costs, including regulatory penalties, fines and legal expenses, and such an event could disrupt our operations, cause us to incur remediation costs, damage our reputation and cause a loss of confidence in us and our or such third parties’ ability to conduct clinical trials, which could adversely affect our reputation and delay our research and development programs.

We or third parties with whom we have relationships may be adversely affected by natural or manmade disasters, and our business continuity and disaster recovery plans may not adequately protect us from a serious disaster.

Natural or manmade disasters could severely disrupt our operations and have a material adverse effect on our business, results of operations, financial condition and prospects. If a natural disaster, power outage or other event occurred that prevented us from using all or a significant portion of our facilities, that damaged our infrastructure or that otherwise disrupted operations, it may be difficult or, in certain cases, impossible for us to continue our business for a substantial period of time, and our research and development activities could be setback or delayed.

The disaster recovery and business continuity plan(s) we have in place may prove inadequate in the event of a serious disaster or similar event. We may incur substantial expenses as a result of the limited nature of our disaster recovery and business continuity plans, which could have a material adverse effect on our business, and such an event could disrupt our operations, cause us to incur remediation costs, damage our reputation and cause a loss of confidence in us and our or third parties’ ability to conduct clinical trials, which could adversely affect our reputation and delay our research and development programs.

We may be subject to claims that our employees, consultants or independent contractors have wrongfully used or disclosed confidential information of third parties or that our employees have wrongfully used or disclosed alleged trade secrets of their former employers.

We may now and in the future employ individuals who were previously employed at universities or other biotechnology or pharmaceutical companies, including our competitors or potential competitors. We may be subject to claims that we or our employees, consultants or independent contractors have inadvertently or otherwise used or disclosed intellectual property, including trade secrets or other proprietary information, of any of our employee’s former employer or other third parties. Litigation may be necessary to defend against these claims. If we fail in defending any such claims, in addition to paying monetary damages, we may lose valuable intellectual property rights or personnel, which could adversely impact our business. Even if we are successful in defending against such claims, litigation could result in substantial costs and be a distraction to management and other employees and consultants.

FINRA sales practice requirements may limit a stockholder’s ability to buy and sell our common stock.

The Financial Industry Regulatory Authority (“FINRA”) has adopted rules requiring that, in recommending an investment to a customer, a broker-dealer must have reasonable grounds for believing that the investment is suitable for that customer. Prior to recommending speculative or low-priced securities to their non-institutional customers, broker-dealers must make reasonable efforts to obtain information about the customer’s financial status, tax status, investment objectives and other information. Under interpretations of these rules, FINRA has indicated its belief that there is a high probability that speculative or low-priced securities will not be suitable for at least some customers. If these FINRA requirements are applicable to us or our securities, they may make it

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more difficult for broker-dealers to recommend that at least some of their customers buy our common stock, which may limit the ability of our stockholders to buy and sell our common stock and could have an adverse effect on the market for and price of our common stock.

We could be subject to securities class action litigation.

In the past, securities class action litigation has often been brought against companies following a decline in the market price of their securities. This risk is especially relevant for us because biotechnology companies have experienced significant share price volatility in recent years. If we face such litigation, it could result in substantial costs and a diversion of management’s attention and resources, which could harm our business.

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SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus contains forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to us. All statements other than statements of historical facts are forward-looking statements. The forward-looking statements are contained principally in, but not limited to, the sections entitled “Prospectus Summary,” “Risk Factors,” “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and “Business.” These statements relate to future events or to our future financial performance and involve known and unknown risks, uncertainties and other factors that may cause our actual results, levels of activity, performance or achievements to be materially different from any future results, levels of activity, performance or achievements expressed or implied by these forward-looking statements. Forward-looking statements include, but are not limited to, statements about:

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In some cases, you can identify forward-looking statements by terms such as “may,” “could,” “will,” “should,” “would,” “expect,” “plan,” “intend,” “anticipate,” “believe,” “estimate,” “predict,” “potential,” “project” or “continue” or the negative of these terms or other comparable terminology. These statements are only predictions. You should not place undue reliance on forward-looking statements because they involve known and unknown risks, uncertainties and other factors, which are, in some cases, beyond our control and which could materially affect results. Factors that may cause actual results to differ materially from current expectations include, among other things, those listed under the heading “Risk Factors” and elsewhere in this prospectus. If one or more of these risks or uncertainties occur, or if our underlying assumptions prove to be incorrect, actual events or results may vary significantly from those implied or projected by the forward-looking statements. No forward-looking statement is a guarantee of future performance.

This prospectus also contains certain data and information, which we obtained from various government and private publications. Although we believe that the publications and reports are reliable, we have not independently verified the data. Statistical data in these publications includes projections that are based on a number of assumptions. If any one or more of the assumptions underlying the market data is later found to be incorrect, actual results may differ from the projections based on these assumptions.

The forward-looking statements made in this prospectus relate only to events or information as of the date on which the statements are made in this prospectus. Although we will become a public company after this offering and have ongoing disclosure obligations under United States federal securities laws, we do not intend to update or otherwise revise the forward-looking statements in this prospectus, whether as a result of new information, future events or otherwise.

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USE OF PROCEEDS

We estimate that the net proceeds from the sale of the             shares of common stock that we are selling in this offering will be approximately $             million, or approximately $            million if the underwriter exercises its over-allotment option in full, assuming an initial public offering price of             $             per share, which is the midpoint of the price range on the cover page of this prospectus, and after deducting estimated underwriting discounts and commissions and estimated offering expenses payable by us.

Each $1.00 increase (decrease) in the assumed initial public offering price of $             per share of our common stock, the midpoint of the estimated price range set forth on the cover page of this prospectus, would increase (decrease) the net proceeds to us from our initial public offering by             $             million, assuming the number of shares offered by us, as set forth on the cover page of this prospectus, remains the same, after deducting estimated underwriting discounts and commissions and estimated offering expenses payable by us.

We currently intend to use the net proceeds from this offering, as follows:

Based on our current operating plan, we believe that the net proceeds from this offering, together with our existing cash and cash equivalents, will be sufficient to fund our operations for at least the next 12 months. In particular, we expect such funds to enable us to complete our three ongoing Phase 2 trials, our ongoing Phase 1b/2 trial and two ongoing Phase 0 trials with ONA-XR, to advance CLDN6xCD3 bsAb to preclinical IND-enablement studies, and to continue to advance our discovery research pipeline. The net proceeds from this offering, together with our existing cash and cash equivalents, will not be sufficient to fund any of our product candidates through regulatory approval, and we anticipate needing to raise additional capital to complete the development of and commercialize our product candidates. It is difficult to predict the cost and timing required to complete development and obtain regulatory approval of, and commercialize, our product candidates due to, among other factors, our lack of experience with initiating, conducting and completing clinical trials, and uncertainty regarding the scope and design of clinical trials required to obtain regulatory approval for our product candidates, the rate of subject enrollment in our clinical trials, filing requirements with various regulatory agencies, clinical trial results, and the actual costs of manufacturing, supplying and commercializing our product candidates.

Our expected use of the net proceeds from this offering represents our intentions based upon our current plans and business conditions. As of the date of this prospectus, we cannot predict with certainty all of the particular uses for the net proceeds to be received upon the completion of this offering or the amounts that we will actually spend on the uses set forth above. We believe opportunities may exist from time to time to expand our current business through licenses with or acquisitions of, or investments in, complementary businesses, products or technologies. While we have no current agreements, commitments or understandings for any specific licenses, acquisitions or investments at this time, we may use a portion of the net proceeds for these purposes.

Our management will have broad discretion over the use of the net proceeds from this offering. The amounts and timing of our expenditures will depend upon numerous factors including the results of our research and development efforts, the timing, cost and success of preclinical studies and any ongoing clinical trials or clinical trials we may commence in the future, the timing of regulatory submissions, our ability to obtain additional financing, the amount of cash obtained through our existing collaborations and future collaborations, if any, and any unforeseen cash needs.

Pending use of the proceeds from this offering as described above, we intend to invest the net proceeds of this offering in short-term, interest-bearing, investment-grade securities or certificates of deposit.

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DIVIDEND POLICY

We currently intend to retain all available funds and any future earnings to fund the development and growth of our business and, therefore, we do not anticipate paying any cash dividends in the foreseeable future. Any future determination to declare dividends will be made at the discretion of our board of directors and will depend on our financial condition, operating results, capital requirements, contractual restrictions, general business conditions and other factors that our board of directors may deem relevant.

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CAPITALIZATION

The following table sets forth our total capitalization as of March 31, 2021:

The pro forma and pro forma as adjusted information below is illustrative only, and our capitalization following the reorganization and the closing of this offering will depend on the actual initial public offering price and other terms of this offering determined at pricing. You should read this table together with our consolidated financial statements, the related notes included elsewhere in this prospectus and the information under “Management’s Discussion and Analysis of Financial Condition and Results of Operations.”

Each $1.00 increase (decrease) in the assumed initial public offering price of $             per             share, the midpoint of the price range listed on the cover page of this prospectus, would increase (decrease) the pro forma as adjusted amount of each of cash and cash equivalents, total assets and total stockholders’ equity by approximately $            , assuming that the number of shares offered by us, as set forth on the cover page of this prospectus, remains the same and after deducting underwriting discounts and commissions and estimated offering expenses payable by us. Similarly, each increase (decrease) of 1.0 million shares in the number of shares offered by us at the assumed initial public offering price per share, the midpoint of the price range listed on the cover page of this prospectus, would increase (decrease) the pro forma as adjusted amount of each of cash and cash equivalents, working capital, total assets and total stockholders’ equity by approximately $             .

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The number of shares outstanding is based on             shares outstanding as of March 31, 2021 and except as noted above, which gives effect to the pro forma transactions described above, and excludes the following currently outstanding securities:

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DILUTION

If you purchase shares of our common stock in this offering, your interest will be diluted to the extent of the difference between the initial public offering price per share and our net tangible book value per share after this offering. Dilution results from the fact that the assumed initial public offering price per share is substantially in excess of the net tangible book value per share attributable to the existing unitholders for our presently outstanding common units.

Our historical net tangible book deficit was approximately $(16.9) million, or $(7.98) per common unit, as of March 31, 2021. Our net tangible book deficit represents the amount of our total consolidated tangible assets (which is calculated by subtracting prepaid offering expenses from our total consolidated assets), less the amount of our total consolidated liabilities less our convertible preferred units divided by the number of our common units.

Our pro forma net tangible book value as of March 31, 2021 was $            , or $             per share. Pro forma net tangible book value per share represents the amount of our total tangible assets less our total liabilities, divided by the number of shares of common stock outstanding as of March 31, 2021, after giving effect to (i) the reorganization, which reflects the automatic conversion of             common units and (ii) the automatic conversion all of our preferred convertible stock outstanding into an aggregate of             shares of common stock and the conversion of              warrants into              shares of common stock immediately prior to the completion of this offering based on an assumed initial public offering price of $             per share, the midpoint of the estimated price range set forth on the cover page of this prospectus.

After giving effect to our issuance and sale of             shares of common stock in this offering at an assumed initial public offering price of $             per share, the midpoint of the estimated price range set forth on the cover page of this prospectus, after deducting estimated underwriting discounts and commissions and estimated offering expenses payable by us, our pro forma, as adjusted net tangible book value as of March 31, 2021 would have been $             or $             per share. This represents an immediate increase in net tangible book value of $             per share to our existing stockholders, and an immediate dilution in net tangible book value of $             per share to new investors. The following table illustrates this per share dilution:

The pro forma information discussed above is illustrative only. Our net tangible book value following the completion of this offering is subject to adjustment based on the actual initial public offering price of our shares and other terms of this offering determined at pricing. A $1.00 increase (decrease) in the assumed initial public offering price of $             per share of common stock, the midpoint of the estimated price range set forth on the cover page of this prospectus, would increase (decrease) our pro forma as adjusted net tangible book value per share after this offering by $             per share and increase (decrease) the dilution to new investors by $             per share, in each case assuming the number of shares of common stock offered by us, as set forth on the cover page of this prospectus, remains the same, and after deducting estimated underwriting discounts and commissions. Similarly, each increase (decrease) of 1.0 million in the number of shares of common stock offered

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by us, as set forth on the cover page of this prospectus, would increase (decrease) the pro forma as adjusted net tangible book value (deficit) per share after this offering by $             per share and increase (decrease) the dilution per share to new investors participating in this offering by $             per share, assuming that the assumed initial public offering price remains the same and after deducting estimated underwriting discounts and commissions and estimated offering expenses payable by us.

If the underwriter exercises in full its option to purchase additional shares of common stock, the pro forma as adjusted net tangible book value (deficit) per share after giving effect to this offering would be $             per share, representing an immediate increase to existing stockholders of $             per share and immediate dilution to new investors participating in this offering of $             per share assuming that the assumed initial public offering price remains the same, and after deducting estimated underwriting discounts and commissions and estimated offering expenses payable by us.

The following table, as of March 31, 2021, on a pro forma as adjusted basis as described above, summarizes the differences between our existing stockholders and the investors purchasing shares in this offering with respect to the number of shares purchased from us, the total consideration paid and the average price per share paid, at the assumed initial public offering price of $             per share, before deducting estimated underwriting discounts and commissions and estimated offering expenses payable by us.

Each $1.00 increase (decrease) in the assumed initial public offering price of $             per share (which is the midpoint of the price range set forth on the cover page of this prospectus), would increase (decrease) the total consideration paid by new investors participating in this offering and total consideration paid by all stockholders by $             million, assuming that the number of shares offered by us, as set forth on the cover page of this prospectus, remains the same and after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us.

The above table assumes no exercise of the underwriter’s option to purchase additional shares. If the underwriter exercises its option to purchase additional shares in full, our existing stockholders before this offering would own             % and our new investors participating in this offering would own             % of the total number of shares of our common stock outstanding immediately prior to the completion of this offering. Additionally, the consideration paid to us by existing stockholders before this offering would be $             million, or approximately             % of the total consideration, and the consideration paid to us by new investors participating in this offering would be $             million, or approximately             % of the total consideration.

The foregoing discussion and tables are based on (other than the historical net tangible book value calculation)             shares outstanding as of March 31, 2021 which gives effect to the pro forma transactions described above, and excludes the following currently outstanding securities:

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To the extent that options or warrants are exercised, new options are issued under our stock incentive plans, or we issue additional shares of common stock in the future, there will be further dilution to investors participating in this offering. In addition, we may choose to raise additional capital because of market conditions or strategic considerations, even if we believe that we have sufficient funds for our current or future operating plans. If we raise additional capital through the sale of equity or convertible debt securities, the issuance of these securities could result in further dilution to our stockholders.

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MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF

OPERATIONS

You should read the following discussion and analysis of our financial condition and results of operations together with the sections titled “Selected Financial Data” and “Prospectus Summary – Summary Financial Information” in this prospectus and our financial statements and the related notes and other financial information included elsewhere in this prospectus. Some of the information contained in this discussion and analysis, including information with respect to our plans and strategy for our business, and the potential impacts of the ongoing COVID-19 pandemic, contains forward-looking statements that involve risks and uncertainties. You should review the section titled “Risk Factors” in this prospectus for a discussion of important factors that could cause actual results to differ materially from the results described below. Please also see the section entitled “Special Note Regarding Forward-Looking Statements.” On April 23, 2021, we completed a reverse triangular merger, resulting in Context Therapeutics Inc. becoming the sole holder of 100% of the membership interests in Context Therapeutics LLC , and which resulted in all of the common units, preferred units and all options, warrants or other rights to purchase common or preferred units of Context Therapeutics LLC converting into common stock, preferred stock and all options, warrants or other rights to purchase common or preferred stock of Context Therapeutics Inc. Prior to the reorganization we operated as Context Therapeutics LLC.

Overview

We are a clinical-stage biopharmaceutical company dedicated to improving the lives of women living with hormone-dependent cancer. Our development team is advancing a pipeline of innovative therapies with a primary focus on treating female, hormone-dependent cancer, including breast, ovarian, and endometrial (uterine) cancer. Our first program and lead product candidate, ONA-XR builds upon a foundation of successful drug development by our management team and advisors in the field of hormone-dependent cancers. ONA-XR is a potent and selective antagonist of the progesterone receptor which has been linked to resistance to multiple classes of cancer therapeutics, including anti-estrogen therapies, across female hormone-dependent cancers.

We were incorporated in April 2015 under the laws of the State of Delaware. Since inception, we have devoted substantially all of our resources to developing product and technology rights, conducting research and development, organizing and staffing our company, business planning and raising capital. We operate as one business segment and have incurred recurring losses, the majority of which are attributable to research and development activities, and negative cash flows from operations. We have funded our operations primarily through the sale of convertible debt and convertible preferred units. Our net loss was $6.4 million for the year ended December 31, 2019 and we had net income of $6.6 million for the year ended December 31, 2020. We also had a net loss of $0.9 million for the three months ended March 31, 2021. As of March 31, 2021, we had an accumulated deficit of $19.7 million. Currently, our primary use of cash is to fund operating expenses, which consist primarily of research and development expenditures, and to a lesser extent, general and administrative expenditures. Our ability to generate product revenue sufficient to achieve profitability will depend heavily on the successful development and eventual commercialization of one or more of our current or future product candidates. We expect to continue to incur significant expenses and operating losses for the foreseeable future as we advance our product candidates through all stages of development and clinical trials and, ultimately, seek regulatory approval. In addition, if we obtain regulatory approval for any of our product candidates, we expect to incur significant commercialization expenses related to product manufacturing, marketing, sales and distribution. Furthermore, upon the closing of this offering, we expect to incur additional costs associated with operating as a public company, including significant legal, accounting, investor relations and other expenses that we did not incur as a private company. Our net losses may fluctuate significantly from quarter-to-quarter and year-to-year, depending on the timing of our clinical trials and our expenses on other research and development activities.

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We expect to continue to incur net operating losses for at least the next several years, and we expect our research and development expenses, general and administrative expenses, and capital expenditures will continue to increase. We expect our expenses and capital requirements will increase significantly in connection with our ongoing activities as we:

We will need to raise substantial additional capital to support our continuing operations and pursue our growth strategy. Until such time as we can generate significant revenue from product sales, if ever, we plan to finance our operations through the sale of equity, debt financings and/or other capital sources, which may include collaborations with other companies or other strategic transactions. There are no assurances that we will be successful in obtaining an adequate level of financing as and when needed to finance our operations on terms acceptable to us or at all. Any failure to raise capital as and when needed could have a negative impact on our financial condition and on our ability to pursue our business plans and strategies. If we are unable to secure adequate additional funding, we may have to significantly delay, scale back or discontinue the development and commercialization of one or more product candidates or delay our pursuit of potential in-licenses or acquisitions.

The COVID-19 Pandemic and its Impacts on Our Business

In March 2020, the World Health Organization declared the outbreak of COVID-19 a global pandemic. The spread of COVID-19 during 2020 has caused worldwide economic instability and significant volatility in the financial markets. There is significant uncertainty as to the likely effects of this disease which may, among other things, materially impact the Company’s planned clinical trials. This pandemic or outbreak could result in difficulty securing clinical trial site locations, contract research organizations (“CROs”), and/or trial monitors and other critical vendors and consultants supporting the trial. In addition, outbreaks or the perception of an outbreak near a clinical trial site location could impact the Company’s ability to enroll patients. These situations, or others associated with COVID-19, could cause delays in the Company’s clinical trial plans and could increase expected costs, all of which could have a material adverse effect on the Company’s business and its financial condition. At the current time, the Company is unable to quantify the potential effects of this pandemic on its future consolidated financial statements.

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Components of Our Results of Operations

Revenue

We have not recognized any revenue from any sources, including from product sales, and we do not expect to generate any revenue from the sale of our products for the foreseeable future. If our development efforts for our product candidates are successful and result in regulatory approval, or license agreements with third parties, we may generate revenue in the future from product sales. However, there can be no assurance as to when we will generate such revenue, if at all.

Operating Expenses

Research and Development Expenses

Research and development expenses have consisted primarily of costs incurred in connection with the discovery and development of our product candidates. We expense research and development costs as incurred, including:

We track outsourced development costs and other external research and development costs to specific product candidates on a program-by-program basis, fees paid to CROs, CMOs and research laboratories in connection with our preclinical development, process development, manufacturing and clinical development activities. However, we do not track our internal research and development expenses on a program-by-program basis as they primarily relate to compensation, early research and other costs which are deployed across multiple projects under development.

Research and development activities are central to our business model. Product candidates in later stages of clinical development generally have higher development costs than those in earlier stages of clinical development, primarily due to the increased size and duration of later-stage clinical trials. We expect our research and development expenses to increase significantly over the next several years as we increase personnel costs, including unit-based compensation, conduct our clinical trials, including later-stage clinical trials, for current and future product candidates and prepare regulatory filings for our product candidates.

General and Administrative Expenses

General and administrative expenses have consisted primarily of personnel expenses, including salaries, benefits and unit-based compensation expense, for employees and consultants in executive, finance and accounting, legal, operations support, information technology and business development functions. General and administrative expense also includes corporate facility costs not otherwise included in research and development expense, including rent, utilities and insurance, as well as legal fees related to intellectual property and corporate matters and fees for accounting and consulting services.

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We expect that our general and administrative expenses will increase in the future to support our continued research and development activities, potential commercialization efforts and increased costs of operating as a public company. These increases will likely include increased costs related to the hiring of additional personnel and fees to outside consultants, legal support and accountants, among other expenses. Additionally, we anticipate increased costs associated with being a public company, including expenses related to services associated with maintaining compliance with the requirements of Nasdaq and the Securities and Exchange Commission, or SEC, insurance and investor relations costs. If any of our current or future product candidates obtain U.S. regulatory approval, we expect that we would incur significantly increased expenses associated with building a sales and marketing team.

Interest Expense

Interest expense has consisted primarily of interest expense related to our Junior Convertible Notes (“Junior Convertible Notes”) and Senior Convertible Notes (“Senior Convertible Notes,” and together with the Junior Convertible Notes, the “Convertible Promissory Notes”) outstanding at December 31, 2019 and 2020, respectively. We expect our interest expense to decrease as our Convertible Promissory Notes have been converted into Series A Units and Series Seed convertible preferred units (“Series Seed Units”). All of the outstanding Convertible Promissory Notes were converted as of February 2021.

Income Taxes

Since our inception, we have not recorded any income tax benefits for the net operating losses (“NOL”) and research and development tax credits generated, as we believe, based upon the weight of available evidence, that it is more likely than not that all of our NOLs and tax credits will not be realized. As of December 31, 2019 and 2020, we had federal and state NOL carryforwards, each in the aggregate amount of $13.2 million and $16.1 million, respectively. As of December 31, 2019 and 2020, we had local NOL carryforwards of $20.4 million and $15.4 million, respectively. The NOL carryforwards begin expiring in 2037 for federal and state income tax purposes, however; all federal NOL carryforwards generated subsequent to January 1, 2018, are able to be carried forward indefinitely. Local NOL carryforwards expire after 3 years with the 2018 NOL set to expire in 2021. As of December 31, 2019 and 2020, the Company had federal research and development tax credit carryforwards of $0.2 million and $0.3 million, respectively, that will begin to expire in 2037, unless previously utilized. We have recorded a full valuation allowance against our net deferred tax assets at each balance sheet date.

Results of Operations

Comparison of the Years Ended December 31, 2019 and 2020

The following table sets forth our results of operations for the years ended December 31, 2019 and 2020:

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Research and Development Expenses

Research and development expenses decreased by $0.8 million from $2.4 million for the year ended December 31, 2019 to $1.6 million for the year ended December 31, 2020. The decrease was mainly due to a decrease in salaries and related benefits of $0.7 million as we reduced our full-time employees and increased third-party contractors to focus solely on developing our product candidates. Additionally, professional fees decreased by $0.3 million. These amounts were partially offset by a $0.2 million increase in preclinical and clinical trial costs as we began our Phase 2 trial in late 2020.

General and Administrative Expenses

General and administrative expenses decreased by $2.1 million from $3.0 million for the year ended December 31, 2019 to $0.9 million for the year ended December 31, 2020. The decrease was mainly due to a decrease in salaries and related benefits of $1.8 million, a decrease in professional fees of $0.2 million and a decrease in facility and other costs of $0.1 million as we reduced our full-time employees and increased third-party contractors to focus solely on developing our product candidates.

Interest Expense

Interest expense decreased by $0.4 million from $1.1 million for the year ended December 31, 2019 to $0.7 million for the year ended December 31, 2020, primarily due to decreased interest recognized in 2020 related to the conversion of our Junior Convertible Notes to Series Seed Units that occurred in May 2020.

Change in Fair Value of Convertible Promissory Notes

The change in fair value of convertible promissory notes was $0.1 million for the year ended December 31, 2019 and $9.9 million for the year ended December 31, 2020. This change was attributable to a decrease in the fair value of our common units.

Comparison of the Three Months Ended March 31, 2020 and 2021

The following table sets forth our results of operations for the three months ended March 31, 2020 and 2021:

Research and Development Expenses

Research and development expenses increased by $0.2 million from $0.2 million for the three months ended March 31, 2020 to $0.4 million for the three months ended March 31, 2021. The increase was mainly due to an increase in contract manufacturing costs of $0.1 million as we continue to develop our first program and lead product candidate ONA-XR. Additionally, preclinical and clinical trial costs increased by $0.1 million as we continued our Phase 2 trial that began in late 2020.

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General and Administrative Expenses

General and administrative expenses increased by $0.1 million from $0.3 million for the three months ended March 31, 2020 to $0.4 million for the three months ended March 31, 2021. The increase was mainly due to an increase in professional fees of $0.2 million related to this offering. This was offset by a decrease of $0.1 million in salaries and related benefits as we reduced our full-time employees to focus solely on developing our product candidates.

Interest Expense

Interest expense decreased by $0.2 million from $0.3 million for the three months ended March 31, 2020 to $0.1 million for the three months ended March 31, 2021 due to the conversion of all convertible promissory notes.

Change in Fair Value of Convertible Promissory Notes

The change in fair value of convertible promissory notes was $1.6 million for the three months ended March 31, 2020 and $9,000 for the three months ended March 31, 2021. This change was attributable to a decrease in the fair value of our common units.

Liquidity and Capital Resources

Overview

Since our inception, we have not recognized any revenue and have incurred operating losses and negative cash flows from our operations. We have not yet commercialized any product and we do not expect to generate revenue from sales of any products for several years, if at all. Since our inception through March 31, 2021, we have funded our operations through the sale of convertible debt and convertible preferred units, receiving aggregate net proceeds of $19.7 million. As of March 31, 2021, we had $1.7 million in cash and cash equivalents and had an accumulated deficit of $19.7 million. In April 2021, we sold 1,712,121 Series A convertible preferred units (“Series A Units”) and issued 428,031 warrants for common member units for gross proceeds of $2.0 million. We expect our existing cash and cash equivalents, together with the anticipated proceeds from this offering will be sufficient to fund our operations for                     . We have based these estimates on assumptions that may prove to be imprecise, and we could utilize our available capital resources sooner than we expect.

Funding Requirements

Our primary use of cash is to fund operating expenses, which consist of research and development expenditures and various general and administrative expenses. Cash used to fund operating expenses is impacted by the timing of when we pay these expenses, as reflected in the change in our outstanding accounts payable, accrued expenses and prepaid expenses.

Because of the numerous risks and uncertainties associated with research, development and commercialization of pharmaceutical products, we are unable to estimate the exact amount of our operating capital requirements. Our future funding requirements will depend on many factors, including, but not limited to:

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We will need additional funds to meet our operational needs and capital requirements for clinical trials, other research and development expenditures, and general and administrative expenses. We currently have no credit facility or committed sources of capital.

Until such time, if ever, as we can generate substantial product revenue, we expect to finance our operations through a combination of equity offerings, debt financings, collaborations, strategic alliances and/or marketing, distribution or licensing arrangements. To the extent that we raise additional capital through the sale of equity or convertible debt securities, your ownership interest will be diluted, and the terms of these securities may include liquidation or other preferences that adversely affect your rights as a common stockholder. Debt financing and preferred equity financing, if available, may involve agreements that include covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, making acquisitions or capital expenditures or declaring dividends. If we raise additional funds through collaborations, strategic alliances or marketing, distribution or licensing arrangements with third parties, we may have to relinquish valuable rights to our technologies, future revenue streams, research programs or product candidates, or grant licenses on terms that may not be favorable to us. If we are unable to raise additional funds through equity or debt financings or other arrangements when needed, we may be required to delay, limit, reduce or terminate our research, product development or future commercialization efforts, or grant rights to develop and market product candidates that we would otherwise prefer to develop and market ourselves.

Cash Flows

The following table shows a summary of our cash flows for the periods indicated:

Comparison of the Years Ended December 31, 2019 and 2020

Operating Activities

During the year ended December 31, 2019, we used $2.8 million of cash in operating activities. Cash used in operating activities reflected our net loss of $6.4 million and the noncash change in fair value of convertible

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promissory notes of $0.1 million, offset by noncash interest expense of $1.1 million, noncash expense related to convertible promissory notes issued in lieu of severance payments of $1.2 million, unit-based compensation expense of $0.8 million, and a decrease in our operating assets and liabilities of $0.6 million.

During the year ended December 31, 2020, we used $1.0 million of cash in operating activities. Cash used in operating activities reflected the noncash change in fair value of convertible promissory notes of $9.9 million, offset by our net income of $6.6 million, noncash interest expense of $0.7 million, unit-based compensation of $0.2 million and a $1.3 million net decrease in our operating assets and liabilities. The primary use of cash was to fund our operations related to the development of our product candidates.

Investing Activities

We did not have cash flows from investing activities for either period presented.

Financing Activities

During the year ended December 31, 2019, financing activities provided $2.0 million from the issuance of convertible promissory notes and convertible bridge notes.

During the year ended December 31, 2020, financing activities provided $1.1 million, consisting of $1.0 million of proceeds from the sale of Series A Units and warrants for common units, $25,000 from the issuance of convertible bridge notes, $50,000 from the sale of Series Seed Units and $0.1 million of proceeds from the Paycheck Protection Program loan.

Comparison of the Three Months Ended March 31, 2020 and 2021

Operating Activities

During the three months ended March 31, 2020, we used $0.2 million of cash in operating activities. Cash used in operating activities reflected the noncash change in fair value of convertible promissory notes of $1.6 million, offset by our net income of $0.8 million, noncash interest expense of $0.3 million, unit-based compensation of $0.1 million and a $0.2 million net decrease in our operating assets and liabilities. The primary use of cash was to fund our operations related to the development of our product candidates.

During the three months ended March 31, 2021, we used $1.7 million of cash in operating activities. Cash used in operating activities reflected our net loss of $0.9 million and an increase in our operating assets and liabilities of $0.9 million. This was offset by non-cash interest expense and unit-based compensation of $0.1 million. The primary uses of cash were to fund our operations related to the development of our product candidates and the preparation of this registration statement.

Investing Activities

We did not have cash flows from investing activities for either period presented.

Financing Activities

During the three months ended March 31, 2020, financing activities provided $25,000 from the issuance of convertible bridge notes.

During the three months ended March 31, 2021, financing activities provided $3.0 million, consisting of net proceeds from the sale of Series A Units and warrants for common units.

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Off-Balance Sheet Arrangements

During the periods presented, we did not have, nor do we currently have, any relationships with unconsolidated entities or financial partnerships, including entities sometimes referred to as structured finance or special purpose entities that were established for the purpose of facilitating off-balance sheet arrangements or other contractually narrow or limited purposes. We do not engage in off-balance sheet financing arrangements. In addition, we do not engage in trading activities involving non-exchange traded contracts. We therefore believe that we are not materially exposed to any financing, liquidity, market or credit risk that could arise if we had engaged in these relationships.

Critical Accounting Policies

This management’s discussion and analysis of our financial condition and results of operations is based on our financial statements, which have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”). The preparation of these consolidated financial statements requires us to make estimates and judgments that affect the reported amounts of assets, liabilities, and expenses and the disclosure of contingent assets and liabilities in our consolidated financial statements. On an ongoing basis, we evaluate our estimates and judgments, including those related to prepaid/accrued research and development expenses, unit-based compensation and fair value of convertible promissory notes. We base our estimates on historical experience, known trends and events, and various other factors that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions.

While our significant accounting policies are described in more detail in Note 3 to our audited consolidated financial statements included elsewhere in this prospectus, we believe the following accounting policies are the most critical to the judgments and estimates used in the preparation of our consolidated financial statements.

Internal Control Over Financial Reporting

Internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements in accordance with U.S. GAAP. Under standards established by the Public Company Accounting Oversight Board, or PCAOB, a deficiency in internal control over financial reporting exists when the design or operation of a control does not allow management or personnel, in the normal course of performing their assigned functions, to prevent or detect misstatements on a timely basis. The PCAOB defines a material weakness as a deficiency, or combination of deficiencies, in internal control over financial reporting, such that there is a reasonable possibility that a material misstatement of annual or interim financial statements will not be prevented, or detected and corrected, on a timely basis.

During the preparation of our consolidated financial statements for the years ended December 31, 2019 and 2020, we and our independent registered public accounting firm identified a material weakness related to the lack of an appropriate review of the internally prepared financial statements which resulted in the Company’s failure to timely detect and correct certain misstatements within the consolidated financial statements. Such misstatements have been corrected in the accompanying consolidated financial statements for the years ended December 31, 2019 and 2020. We also identified a material weakness as it relates to a lack of adequate segregation of accounting functions.

We are in the process of implementing measures designed to improve our internal control over financial reporting to remediate these material weaknesses. Our plan to remediate the material weaknesses in our internal control over financial reporting includes utilizing a portion of the working capital from our initial public offering to increase staffing within our accounting infrastructure sufficient to facilitate proper segregation of accounting functions and to enable appropriate review of our internally prepared consolidated financial statements. In addition, we plan to retain outside consultants, expert in, and specializing in technical accounting and SEC reporting for public company registrants.

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Research and Development Expenses

Research and development expenses consist primarily of costs incurred in connection with the development of our product candidates. We expense research and development costs as incurred.

We accrue an expense for preclinical studies and clinical trial activities performed by our vendors based upon estimates of the proportion of work completed. We determine the estimates by reviewing contracts, vendor agreements and purchase orders, and through discussions with our internal clinical personnel and external service providers as to the progress or stage of completion of trials or services and the agreed-upon fee to be paid for such services. However, actual costs and timing of clinical trials are highly uncertain, subject to risks and may change depending upon a number of factors, including our clinical development plan.

We make estimates of our prepaid/accrued expenses as of each balance sheet date in our consolidated financial statements based upon facts and circumstances known at that time. If the actual timing of the performance of services or the level of effort varies from the estimate, we will adjust the accrual accordingly. Nonrefundable advance payments for goods and services, including fees for clinical trial expenses, process development or manufacturing and distribution of clinical supplies that will be used in future research and development activities, are deferred and recognized as expense in the period that the related goods are consumed, or services are performed.

Unit-Based Compensation

We measure compensation expense for all unit-based awards based on the estimated fair value of the unit-based awards on the grant date. We use the Black-Scholes option pricing model to value our unit-based awards. We recognize compensation expense on a straight-line basis over the requisite service period, which is generally the vesting period of the award. We have not issued awards for which vesting is subject to market or performance conditions.

The Black-Scholes option-pricing model requires the use of subjective assumptions that include the expected stock price volatility and the fair value of the underlying common stock on the date of grant. See Note 7 to our audited consolidated financial statements included elsewhere in this prospectus for information concerning certain of the specific assumptions we used in applying the Black-Scholes option pricing model to determine the estimated fair value of our awards granted.

The following table summarizes by grant date the number of common member units subject to options granted from January 1, 2019 to May 1, 2021, as well as the associated per share exercise price and the estimated fair value per unit of our common member units as of the grant date:

Based on the initial public offering price of $            per share of common stock, which is the midpoint of the price range on the cover page of this prospectus, the aggregate intrinsic value of vested and unvested unit options outstanding as of March 31, 2021 was $            million and $            million, respectively.

Estimating the Fair Value of Common Stock

We are required to estimate the fair value of the common stock underlying our unit-based awards when performing the fair value calculations using the Black-Scholes option pricing model. Because our common

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member units are not currently publicly traded, the fair value of the common stock underlying our unit options has been approved on each grant date by our board of managers or board of directors, as applicable, with input from management.

The third-party valuations of our common stocks were performed using methodologies, approaches and assumptions consistent with the American Institute of Certified Public Accountants, Audit and Accounting Practice Aid Series: Valuation of Privately Held Company Equity Securities Issued as Compensation. In addition, our board of managers and board of directors considered various objective and subjective factors to estimate the estimated fair value of our common member units, including:

In determining the estimated fair value of our common member units, our board of managers considered the subjective factors discussed above in conjunction with the most recent valuations of our common member units that were prepared by an independent third party. An independent valuation specialist was utilized by our board of managers when determining the estimated fair value of common member units for the awards granted from February 2020 through February 2021. Our board of managers, relying on these third-party valuations, approved valuations of our common member units of $2.26 per share as of February and April 2020, $0.31 per share as of May 2020 and $0.29 per share as of February 2021. Additionally, our board of directors, approved a valuation of our common stock of $0.29 as of April 2021. In making such determination in April 2021, our board of directors considered the private placement of our Series A Units and warrants that occurred during the three months ended March 31, 2021 as well as other factors our board of directors deemed appropriate.

Following the closing of this offering, the fair value of our common stock will be the closing price of our common stock on the Nasdaq Capital Market as reported on the date of the grant.

Estimating the Fair Value of Convertible Notes

We have elected the fair value option for the accounting for our convertible notes issued since inception and utilized an independent third-party valuation specialist to assist management in measuring the fair value. The fair value of the Junior Convertible Notes at December 31, 2019 was estimated using a Contingent Claims Analysis, also called the Option Pricing Method (“OPM”). The model estimated the fair value of the convertible

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promissory notes based on accrued interest, the expected timing of a future liquidity event and the value of a future liquidity event. Because the Company’s capital structure varied, it was necessary to value the securities in a lattice framework rather than using the Black-Scholes-Merton formula. The fair value of the Senior Convertible Notes at December 31, 2020 was calculated using an OPM framework and utilized the back-solve method for inferring and allocating the equity value predicated on the concurrent sale of Series A Units. This method was selected as we concluded that the sale of the Series A Units was an arm’s-length transaction. Application of the OPM back-solve method involves making assumptions for the expected time to liquidity and volatility, and then solving for the value of equity such that value for the most recent financing equals the amount paid.

Recent Accounting Pronouncements

See Note 3 to our audited consolidated financial statements found elsewhere in this prospectus for a description of recent accounting pronouncements applicable to our consolidated financial statements.

Qualitative and Quantitative Disclosures About Market Risk

We are exposed to market risk related to changes in interest rates. As of March 31, 2021, we had cash and cash equivalents of $1.7 million consisting of bank deposits and a commercial money market account. Due to the short-term duration of our cash equivalents, an immediate 10% change in interest rates would not have a material effect on the fair market value.

Inflation generally affects us by increasing our labor and clinical trial costs. We do not believe inflation had a material effect on our business, financial condition or results of operations during the years ended December 31, 2019 and 2020.

Emerging Growth Company and Smaller Reporting Company Status

In April 2012, the Jumpstart Our Business Startups Act of 2012, or the JOBS Act, was enacted. Section 107 of the JOBS Act provides that an “emerging growth company” can take advantage of the extended transition period provided in Section 7(a)(2)(B) of the Securities Act of 1933, as amended, for complying with new or revised accounting standards. Thus, an emerging growth company can delay the adoption of certain accounting standards until those standards would otherwise apply to private companies. We have elected to avail ourselves of this exemption from complying with new or revised accounting standards and, therefore, will not be subject to the same new or revised accounting standards as other public companies that are not emerging growth companies. As a result, our financial statements may not be comparable to companies that comply with new or revised accounting pronouncements as of public company effective dates.

We are in the process of evaluating the benefits of relying on other exemptions and reduced reporting requirements under the JOBS Act, including without limitation, exemption to the requirements for providing an auditor’s attestation report on our system of internal controls over financial reporting pursuant to Section 404(b) of the Sarbanes-Oxley Act. We will remain an emerging growth company until the earlier to occur of (a) the last day of the fiscal year (i) following the fifth anniversary of the completion of this offering, (ii) in which we have total annual gross revenues of at least $1.07 billion or (iii) in which we are deemed to be a “large accelerated filer” under the rules of the SEC, which means that we have been required to file annual and quarterly reports under the Exchange Act for a period of at least 12 months and have filed at least one annual report pursuant to the Exchange Act and either (a) the market value of our common stock that is held by non-affiliates exceeds $700.0 million as of the prior June 30th, or (b) the date on which we have issued more than $1.0 billion in non-convertible debt during the prior three-year period.

We are also a “smaller reporting company,” meaning that the market value of our stock held by non-affiliates plus the proposed aggregate amount of gross proceeds to us as a result of this offering is less than $700.0 million and our annual revenue is less than $100.0 million during the most recently completed fiscal year. We may continue to be a smaller reporting company after this offering if either (i) the market value of our stock held by non-affiliates is less than $250.0 million or (ii) our annual revenue is less than $100.0 million during the

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most recently completed fiscal year and the market value of our stock held by non-affiliates is less than $700.0 million. If we are a smaller reporting company at the time we cease to be an emerging growth company, we may continue to rely on exemptions from certain disclosure requirements that are available to smaller reporting companies. Specifically, as a smaller reporting company we may choose to present only the two most recent fiscal years of audited financial statements in our Annual Report on Form 10-K and, similar to emerging growth companies, smaller reporting companies have reduced disclosure obligations regarding executive compensation.

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BUSINESS

Overview

We are a clinical-stage biopharmaceutical company dedicated to improving the lives of women living with cancer.

Profound advancements in oncology drug development have expanded the treatment options available to women with cancer, yet therapeutic resistance and relapse continue to limit the efficacy and duration of such treatments. Collectively, our founders and management team have decades of experience identifying and characterizing the mechanisms that drive cancer initiation and subsequent relapse in women with cancer and who have been associated with the development of products such as Kisqali (ribociclib), Arimidex (anastrozole), and Afinitor (everolimus) to treat such cancers.

Our development team is advancing a pipeline of innovative therapies with a primary focus on treating female cancers. Our first program and lead product candidate, onapristone extended release (“ONA-XR”), builds upon a foundation of successful drug development by our management team and advisors in the field of female hormone-dependent cancers. ONA-XR is a selective and potentially potent antagonist of the progesterone receptor (PR), a receptor that is activated by the hormone progesterone and that has been linked to resistance to multiple classes of cancer therapeutics, including anti-estrogen therapies, that are prescribed to treat female hormone-dependent cancers. In 2019, we initiated a Phase 2 investigator-sponsored trial in collaboration with Memorial Sloan Kettering Cancer Center to evaluate ONA-XR in women with ovarian cancer who express high levels of progesterone receptor (PR+) and we expect to report preliminary data from this trial in the second half of 2021. In 2020, we initiated a Phase 2 investigator-sponsored trial in collaboration with Thomas Jefferson University to evaluate ONA-XR in combination with Arimidex (anastrozole) in PR+ endometrial cancer and we initiated a Phase 0 trial of ONA-XR in a window of opportunity study in primary breast cancer, and we expect to report preliminary data in the first half of 2022 and final data in late 2022 for each trial, respectively. The window of opportunity study is a three week study in women with primary breast cancer and subsequent lumpectomy to evaluate the direct effects of ONA-XR on the cancer signaling pathways and the tumor microenvironment. In 2021, a Phase 1b/2 investigator-sponsored trial was initiated in collaboration with Memorial Sloan Kettering Cancer Center to evaluate ONA-XR in combination with Ibrance (palbociclib) and Femara (leterozole) in first line metastatic breast cancer patients with biochemically recurrent disease, defined as circulating tumor DNA (ctDNA) positive. This is potentially a new clinical opportunity for the estimated 20% of 1L patients who are at high risk of early disease progression on Ibrance and Femara therapy. Also in 2021, a Phase 2 investigator-sponsored trial was initiated in collaboration with Wisconsin Oncology Network to evaluate ONA-XR in combination with Faslodex (fulvestrant) in second or third line metastatic breast cancer. This trial is intended to establish ONA-XR plus Faslodex drug synergy after treatment failure of CDK4/6 inhibitor and/or PIK3α inhibitors. We expect to report preliminary data from one of these trials in the first half of 2022. In 2021, we also initiated a sub-study of our Phase 2 trial in 2L/3L metastatic breast cancer, which evaluates the uptake of radiolabeled progesterone (F-FFNP) via PET imaging in breast tumors, with preliminary data expected to come in the first half of 2022. Our second program, CLDN6xCD3 bsAb, is an anti-CD3 x anti-Claudin 6 (CLDN6) antigen bispecific monoclonal antibody (bsAbs) that is intended to redirect T-cell-mediated lysis toward malignant cells expressing CLDN6. CLDN6 is a tight junction membrane protein target expressed in multiple cancers, including ovarian and endometrial tumors, and absent from healthy adult tissues. We expect to enter IND-enabling studies for CLDN6xCD3 bsAb in 2022. Beyond these two product candidates, we have a discovery-stage program evaluating antagonists of Sigma1 for breast and prostate cancer. We believe our team and capabilities uniquely position us to be a leader in developing novel therapies to address female hormone-dependent cancers.

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Context retains worldwide development and commercialization rights for ONA-XR outside of Greater China and retains full worldwide development and commercialization rights to certain CLDN6 antibody patents in the field of bispecific antibodies and to certain patents related to Sigma1. Our product candidates are shown in the figure below:

Our Product Pipeline and Development

PR antagonist program: ONA-XR

Currently, there are no approved therapies that selectively target progesterone receptor positive (PR+) cancers. Preclinical and clinical data suggest that onapristone extended release (ONA-XR) has anticancer activity by inhibiting PR binding to chromatin, downregulating cancer stem cell mobilization and blocking immune evasion. ONA-XR is currently being evaluated in three Phase 2 trials, one Phase 1b/2 trial and two Phase 0 biomarker pharmacodynamic trials in women with primary or metastatic breast, ovarian, and endometrial cancers. These trials are intended to establish safety, pharmacokinetics, pharmacodynamics, and anti-tumor activity at the recommended Phase 2 dose of ONA-XR to guide potential advancement in Phase 3 development in 2023.

To help inform which patients may be most suitable for treatment with ONA-XR, we are evaluating multiple biomarker assays, including tools to monitor activated progesterone receptor as well as a PR gene activation signature that measures PR signaling activity, both of which are being utilized in our ongoing clinical trials and may be used for patient selection in future clinical trials. We expect to report preliminary data from at least one Phase 2 trial in the first half of 2021 and from the other trials in the second half of 2022.

CLDN6xCD3 bispecific antibody program

Our second program, CLDN6xCD3 bsAb, is an anti-CD3 x anti-Claudin 6 (CLDN6xCD3) antigen bispecific monoclonal antibody (bsAbs) that is intended to redirect T-cell-mediated lysis toward malignant cells expressing CLDN6. CLDN6 is a tight junction membrane protein target expressed in multiple hormone-dependent cancers, including ovarian and endometrial tumors, and absent from healthy adult tissues. The structural complexity of CLDN6 and its similarity to proteins expressed on healthy tissue, particularly Claudin 4 and Claudin 9 (CLDN9), have limited its exploitation for targeted oncology therapies. Several global pharmaceutical companies are developing anti-CLDN6 antibodies, but due to significant antibody selectivity challenges, to our knowledge, there are no selective inhibitors of CLDN6 in clinical development. We expect to enter IND-enabling studies for CLDN6xCD3 bsAb in 2022.

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Other preclinical programs

In addition to our product candidates, we are leveraging our knowledge in hormone-dependent cancers to pursue discovery stage research programs, including Sigma1. Sigma1 is a cellular protein that regulates homeostasis and has been shown to play a role in breast and prostate cancer. The Sigma1 discovery research program is currently in lead optimization and has undergone in vivo studies.

Our Management Team

We have assembled a management team to develop novel products to treat female hormone-dependent cancers. Members of our management team have experience leading organizations that have advanced multiple oncology therapeutics from early-stage research to clinical trials, and ultimately to regulatory approval and commercialization. Our team’s select accomplishments include:

We are supported by our advisors who are leading experts in hormone-dependent cancer and anti-estrogen resistance, including Dr. Carol Lange, Dr. Larry Norton, and Dr. Felix Kim, a co-founder of Context. Our arrangements with these individuals do not entitle us to any of their existing or future intellectual property derived from their independent research or research with other third parties beyond what has previously been licensed to us.

Strategy

Our goal is to develop and commercialize innovative and differentiated oncology products that address significant unmet medical needs in the field of female cancer, with a primary focus on the hormone-dependent subcategory. The key components of our strategy to achieve this goal include:

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Our focus on female hormone-dependent cancer

Up to 70% of women with breast, ovarian, and endometrial cancer have hormone-dependent cancer. The hormones estrogen and progesterone drive cancer progression in those patients, but anti-estrogens are the only antihormonal therapy that is FDA approved and available to clinicians. Therefore, treatment of those patients to date has consisted of anti-estrogens alone or in combination with drugs that enhance the antitumor activity of anti-estrogens, including inhibitors of CDK4/6 or PI3Kα. Given the broad use of anti-estrogens, anti-estrogen resistance is now a major clinical challenge. Treatment options for anti-estrogen resistance are limited, provide modest therapeutic benefit, and are associated with side effects.

Estrogen and progesterone are master regulators of normal female sex organ development and function, acting via estrogen receptors (“ER”) and progesterone receptors (“PR”). Mechanistically, published data suggest that in hormone-dependent cancers, ER and PR are often hyperactive, constantly pushing breast, ovary, and endometrial tissues to grow, divide, and metastasize. One such strategy to block this hormone-mediated growth is to administer anti-estrogen therapy (fulvestrant, letrozole, anastrozole, or tamoxifen), which may be used in combination with inhibitors of CDK4/6 or PI3Kα to enhance anti-estrogen mediated effects. However, the cancer cells respond to this selective pressure of ER inhibition by further activating progesterone signaling as a compensatory mechanism, along with other resistance mechanisms that can further activate PR, including ER ligand binding mutations (ESR1), growth factor signaling, and enrichment of cancer stem cells. Over time, it is believed that all patients become resistant to anti-estrogens due to direct or indirect compensatory signaling mediated by the PR and other factors. These findings suggest that progesterone receptor and proteins that regulate PR could represent promising drug targets to address anti-estrogen resistance.

Overview of antiestrogen resistance mechanisms

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We are building a portfolio of novel agents targeting multiple anti-estrogen resistance mechanisms by leveraging our specialized expertise in hormone-dependent cancers.

PR antagonist program: ONA-XR

Published data suggest that the PR signaling pathway is implicated in resistance to anti-estrogen therapies in female hormone-dependent cancer, including breast, ovarian, and endometrial cancer. Our clinical development effort for ONA-XR, a selective and potentially potent small molecule antagonist of PR, will initially focus on indications where there is evidence suggesting PR-mediated signaling contributes to resistance and disease progression. In 2019, a Phase 2 investigator-sponsored trial was initiated in collaboration with Memorial Sloan Kettering Cancer Center to evaluate ONA-XR in women with ovarian cancer who express high levels of progesterone receptor (PR+) and we expect to report preliminary data from this trial in the second half of 2021. In 2020, a Phase 2 investigator-sponsored trial was initiated in collaboration with Thomas Jefferson University to evaluate ONA-XR in combination with Arimidex (anastrozole) in PR+ endometrial cancer and we initiated a Phase 0 trial of ONA-XR in a window of opportunity study in primary breast cancer, and we expect to report preliminary data in the first half of 2022 and final data in late 2021 for each trial, respectively. In 2021, a Phase 1b/2 investigator-sponsored trial was initiated in collaboration with Memorial Sloan Kettering Cancer Center to evaluate ONA-XR in combination with Ibrance (palbociclib) and Femara (leterozole) in first line metastatic breast cancer patients with biochemically recurrent disease, defined as circulating tumor DNA (ctDNA) positive. This is potentially a new clinical opportunity for the estimated 20% of 1L patients who are at high risk of early disease progression on Ibrance and Femara therapy. Also in 2021, a Phase 2 investigator-sponsored trial was initiated in collaboration with Wisconsin Oncology Network to evaluate ONA-XR in combination with Faslodex (fulvestrant) in 2L/3L metastatic breast cancer. This trial is intended to establish ONA-XR plus Faslodex drug synergy after treatment failure of CDK4/6 inhibitor and/or PIK3α inhibitors. We expect to report preliminary data from one of these trials in the first half of 2022. In 2021, we also initiated a sub-study of our Phase 2 trial in 2L/3L metastatic breast cancer, which evaluates the radiolabeled progresterone uptake in breast tumors, with preliminary data expected to come in the first half of 2022.

Progesterone receptor background

Progesterone receptor (PR) is a member of the nuclear hormone receptor family of ligand-dependent transcription factors that is expressed primarily in female reproductive tissues. In response to the endogenous steroid hormone, progesterone, PR regulates the expression of gene networks to control development, differentiation, and proliferation of target tissues and the pathological processes in endocrine-based cancers. Anti-progestins are a class of nuclear receptor ligands that act to antagonize PR by binding to the progesterone binding site within the PR-ligand binding domain.

Recently, the role of progesterone in carcinogenesis has gained further clarity. Mechanistically, published data suggest that progesterone promotes oncogenic progression and maintenance of stem cells, creating a reservoir of pre-malignant cells to seed metastasis. Initial evidence for this tumorigenic role is derived from longitudinal studies of the use of hormone replacement therapy in menopausal women. As shown in the figure below, these studies determined that supplemental estrogen was associated with a 23% decrease in cancer risk, whereas supplemental progesterone was associated with a 25% increase in cancer risk. The results demonstrated that women who were consistently exposed to progesterone had a higher risk of developing breast cancer than those who did not. This finding was confirmed by published data wherein mice treated with progesterone exhibited enhanced breast tumor growth whereas progesterone receptor inhibition via genetic knockdown conversely inhibited tumor growth.

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Association of progesterone and breast cancer risk

Source: Reprinted from the Journal of the American Medical Association Oncology, Chlebowski et al, Breast Cancer After Use of Estrogen Plus Progestin and Estrogen Alone: Analyses of Data From 2 Women’s Health Initiative Randomized Clinical Trials, Copyright 2015. Reprinted with permission from American Medical Association.

Note: CEE: synthetic estrogen; E: estrogen; HRT: hormone replacement therapy; MPA: synthetic progesterone; P: progesterone.

As shown in the figure below, PR can be activated by ligand (progesterone) or ligand-independent (pos-translational modifications) mechanisms. Consistent with other steroid hormone receptor family members, PR is heavily post-translationally modified and thus acts as a molecular sensor for abnormally elevated or active signaling pathways. Little overlap exists between PR transcriptomes assayed in normal relative to neoplastic cells. In cancer cells, posttranslational modifications (namely, phosphorylation and SUMOylation) create unique PR species whose altered behavior as ligand-dependent transcription factors is predicted to impact tumor initiation and progression. Due to the breadth of post-translational modifications of PR, there is limited selective mutational pressure to modify PR itself - thus, PR mutations are rare. However, when present, the PR mutations have a profound impact on PR activity and tumorigenesis.

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Illustrative mechanism of action

Note: ER: estrogen receptor; ESR1^Y537S: estrogen receptor mutation.

The progesterone receptor as a mechanism of resistance

Recently, progesterone receptor has emerged as anti-estrogen resistance mechanism. Long term exposure of cancer cells to anti-estrogens results in a complex resistance profile that limits the utility of standard of care anti-estrogen and cyclin-dependent kinase 4/6 (CDK4/6) inhibitors. Mechanisms of resistance include mutations in the estrogen receptor (ESR1) estrogen binding domain and ER pathway signaling (e.g., MAPK, PI3Kα/mTOR proteins and associated signaling pathways). The prevalence of resistance mutations is associated with PR enrichment and activity. Based on our preclinical data and recent published data, we believe therapeutic inhibition of PR with either ONA-XR alone or in combination with anti-estrogens and/or CDK4/6 inhibitors may result in the impaired growth or death of resistant cells.

Limitations of other PR antagonists

Anti-progestins, the therapeutic inhibitors of PR, were first developed as oral contraceptives to block the maturation of the endometrium and subsequent ovulation. The first commercially available anti-progestin, Korlym (mifepristone), is a steroid derivative that acts both as a competitive progesterone receptor (PR) antagonist and as a partial PR agonist, depending on the physiological milieu. Mifepristone is approved for controlling hyperglycemia secondary to hypercortisolism in adult Cushing’s syndrome associated with Type 2 diabetes. Mifepristone was also clinically evaluated in breast and ovarian carcinomas, and while showing evidence of efficacy in clinical studies, mifepristone was also associated with off-target glucocorticoid receptor (GR) modulation leading to cortisolemia and rare cases of cholestasis. In order to optimize PR antagonism while minimizing off-target activities, additional anti-progestins—including ulipristal, telapristone, lonaprisan and onapristone—were developed and evaluated in gynecological cancer.

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Illustrative comparison of progesterone receptor antagonists

Note: AR: androgen receptor; C-13: carbon 13; n.a.: not applicable;1L mBCa: first-line metastatic breast cancer.

ONA-XR differentiation

Onapristone is a competitive PR antagonist that has no intrinsic activity for activating the receptor. As such, onapristone is also termed a “full” PR antagonist (inhibitor). Based on published data, all other anti-progestins that have reached the clinic demonstrate partial PR agonism. This differentiation may have a structural basis. It is well established that high energy, conformationally complex chemicals have improved selectivity and target affinity relative to low energy, flat counterparts. As shown above, all other anti-progestins have a roughly planar ring, low energy, A thru D conformation. In contrast, onapristone shows an inversion of stereochemistry at the C-13 methyl group that results in a high energy, chair conformation. This structural property is unique among clinically evaluated anti-progestins and may be important for onapristone’s full PR antagonist properties, as shown below.

Onapristone PR binding properties vs. other anti-progestins and progesterone

Source: Reprinted from Steroids, Elger et al, Endocrine pharmacological characterization of progesterone antagonists and progesterone receptor modulators with respect to PR-agonistic and antagonistic activity, Copyright 2000. Reprinted with permission from Elsevier.

Note: RU 486: mifepristone; J 867: asoprisnil; Ona: onapristone.

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Classic in vitro models have provided limited benefit in determining PR agonist versus antagonist properties. As the cost of gene expression profiling has decreased considerably over the last decade, it is now feasible to run comparative studies to determine how compounds are affecting the expression, positively or negatively, of target genes. Afhuppe et al (2009) conducted the first such study comparing anti-progestins in a gene array panel. T47D breast cancer cells (ER+, PR+) were grown in 2D, stimulated with estrogen (estradiol), and treated with anti-progestins. An Affymetrix^® gene chip analysis of the cells was then conducted to determine transcriptional activity on the level of target genes. Onapristone demonstrated the purest PR antagonist activity as indicated downregulation (green blocks) of almost all PR target genes analyzed, whereas mifepristone had a transcriptional profile closer to R5020, which is pure progesterone.

Modulation of PR signaling genes by different anti-progestins

Source: Reprinted from The Journal of Steroid Biochemistry and Molecular Biology, Afhüppe et al, Global gene expression profiling of progesterone receptor modulators in T47D cells provides a new classification system, Copyright 2009. Reprinted with permission from Elsevier.

Anti-progestin clinical trial data

In subjects with breast cancer, clinical trials with mifepristone, lonapristone and onapristone demonstrated partial responses. Onapristone clinical efficacy in breast cancer was studied in two Phase 1-2 clinical studies treating hormone therapy-naïve and tamoxifen-resistant metastatic breast cancer, while the safety component of a third Phase 1-2 study has been reported by Cottu et al. (2018). The earlier onapristone trials in breast cancer dosed orally with a simple solid dosage form (an “immediate release” or “IR” form; onapristone IR; ONA-IR), ONA-IR 100mg once per day (QD), for periods exceeding 12 months. The third breast cancer study used the extended release form, ONA-XR, dosed at 50mg twice per day (BID). Robertson et al (1999) reported a 67% clinical benefit rate (CBR), defined as tumor shrinkage or tumor growth stabilization lasting for more than 6 months, while Jonat et al (2002) reported a 49% CBR. Both studies, therefore, indicated that onapristone could have a clinically meaningful impact on treatment of hormone-dependent breast cancer. Clinical development of ONA-IR for use in reproductive medicine and benign gynecological conditions was discontinued by the original sponsor (Schering AG), possibly due to concerns around drug-induced liver injury.

The extensive use of anti-estrogens, together with efficacy limits with earlier anti-progestins, has led to renewed interest in anti-progestins as therapies for breast and gynecologic cancer, as well as for uterine fibroids and endometriosis. Compared to earlier anti-progestin clinical trials, we believe we have a better tolerated formulation of onapristone (ONA-XR) and we will be able to better identify those patients who are most likely to benefit from anti-progestin therapy through the incorporation of biomarkers in our trials.

Our current opportunities for ONA-XR

Within the G7 (EU5, Japan, US) countries, it is estimated that there are over 355,000 patients living with metastatic breast, ovarian, or endometrial cancer. Up to 70% of these patients are expected to be progesterone receptor positive and would potentially be eligible for treatment with ONA-XR.

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Prevalence in G7 countries for metastatic breast, ovarian, and endometrial cancers

Source: secondary epidemiologic estimates, 2020 estimates.

Note: EU5: France, Germany, Italy, Spain, United Kingdom.

Resistance to anti-estrogen therapy in breast cancer

We have chosen PR antagonism in breast cancer as our initial therapeutic focus due to the well-documented biology of PR signaling as a mechanism of resistance to anti-estrogen therapy in patients with hormone-dependent breast cancer. Hormone-dependent breast cancer cells express estrogen (ER) and/or progesterone receptors (PR) that allow the cells to grow in the presence of the hormones estrogen and/or progesterone. Published data suggests that PR signaling is predominantly required for breast cancer cell renewal (i.e., stemness) and metastatic spread, whereas ER is predominantly required for breast cancer cell proliferation. By combining anti-progestin and anti-estrogen therapy, we have shown preclinically that breast cancer cell growth, renewal, and spread can be mitigated. Based on these data, we believe that ONA-XR, in combination with current standard-of-care anti-estrogens, has the potential to significantly improve clinical outcomes.

Breast cancer overview

Breast cancer is the most frequent cancer among women, impacting 2.1 million women globally each year, and causing the greatest number of cancer-related deaths among women. In 2018, it is estimated that 627,000 women died from breast cancer worldwide — that is approximately 15% of all cancer deaths among women according to the World Health Organization. According to the American Cancer Society, the prevalence of women in the United States living with adjuvant, first line metastic, or second/third line metastatic breast cancer are an estimated 250,000, 75,000, and 35,000 respectively.

Breast cancer treatment is primarily determined by the presence or absence of three proteins: estrogen receptor (ER), progesterone receptor (PR), and HER2. The presentation of these proteins determines the subtype of breast cancer, which helps determine the optimal form of treatment for the patient. Patients who are ER+,PR+,HER2- are considered to be hormone receptor positive (i.e., hormone-dependent) and represent about 70% of breast cancers. HER2+ patients and triple negative patients (ER-,PR-,HER2-) represent the remaining 30% of breast cancers.

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Estrogen-deprivation (anti-estrogen) therapy is the core treatment modality in patients with hormone receptor positive metastatic breast cancer according to NCCN Guidelines^®. Anti-estrogen therapy options for postmenopausal women with ER+ advanced breast cancer include:

In addition, cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors are rapidly transforming the care of patients with ER+,HER2- advanced breast cancer. There are currently three CDK4/6 inhibitors that have been approved by the U.S. Food and Drug Administration: Ibrance, Kisqali, and Verzenio. It is generally recommended to use the combination of a CDK4/6 inhibitor along with an aromatase inhibitor (i.e., letrozole) for first line locally advanced or metastatic breast cancer treatment.

Illustrative breast cancer treatment landscape

Note: ORR: overall response rate; PFS: progression free survival.

Upon first line disease progression, second line therapy is most often fulvestrant (anti-estrogen) or fulvestrant plus alpelisib (Piqray), a PI3Kα inhibitor, if the patients have PIK3CA-mutated hormone receptor-positive breast cancer. Fulvestrant plus Piqray was FDA approved in 2019 based on a Phase III trial of 572 patients that demonstrated a progression free survival (PFS) of 11.0 months vs. 5.7 months in the Piqray plus fulvestrant arm compared with fulvestrant alone (HR, 0.65, 95% CI 0.50–0.85). However, a total of 25% of patients discontinued Piqray plus fulvestrant therapy due to toxicities, thus, emphasizing the need for novel agents. Upon progression on second line therapy, mammalian target of rapamycin (mTOR) inhibitors, including everolimus (Afinitor), plus anti-estrogen based regimen or chemotherapy is administered. One key limitation of both the Afinitor and Piqray studies is the lack of data for the role of these agents after prior CDK4/6 inhibitor therapy. Most patients progress on these treatments and ultimately develop resistance. At that time, patients typically live for less than two years.

Preclinical data

The female ovarian hormones estrogen and progesterone are master regulators of normal breast development and play a key role in breast cancer. Acting through ER and PR, estrogen and progesterone play complex, essential, and coordinated roles in the development of the lobular alveolar epithelial structures of the normal breast during puberty, the normal menstrual cycle, and pregnancy. It is likely that these actions become subverted in the development of breast cancer, implicating both estrogen and progesterone in the development and progression of this disease. Breast cancer is acknowledged to be a hormone-dependent disease and most

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breasts express ER and/or PR. PR is expressed in humans as two major forms, progesterone receptor A (PR-A) and progesterone receptor B (PR-B), in normal cells and in certain malignant tissues. PR-A and PR-B mediate the effects of progesterone by association with a range of co-regulatory proteins and progesterone-regulated gene promoters. Over the past few decades, the estrogen receptor signaling pathway remains the most effective treatment for the management of ER+ breast cancer. Treatments include the selective estrogen receptor modulator (SERM) tamoxifen that binds to ER and prevents its activation, and aromatase inhibitors that block endogenous hormone synthesis.

Recent published data suggests that progesterone receptor may function as an anti-estrogen resistance mechanism. Long term exposure of cancer cells to anti-estrogens results in a complex resistance profile that limits the utility of standard of care anti-estrogen and CDK4/6 inhibitors. Mechanisms of resistance include mutations in estrogen receptor gene (ESR1) and ER pathway signaling (MAPK, PI3Kα, mTOR), as 20-35% of ER+,PR+,HER2-metastatic breast tumors are ESR1 mutated. The prevalence of resistance mutations is correlated with PR enrichment and activity. We have presented data showing that therapeutic inhibition of PR with either onapristone alone or in combination with anti-estrogens and/or CDK4/6 inhibitors results in the impaired growth or death of resistant cells.

As shown below, estrogen receptor (ESR1) mutational profiles of tumor biopsies were taken before and after prolonged treatment with anti-estrogen (fulvestrant) and CDK4/6 inhibitor (palbociclib) therapy. ESR1^Y537S mutations are enriched by the end of therapy and are associated with worse outcomes in patients. To determine the effect of ESR1 mutations, wild type (ESR1) and mutant (ESR1^Y537S and ESR1^Y537N) estrogen receptors were overexpressed in the T47D breast cancer cell line. The orange box denotes that both the PR-A and PR-B isoforms of progesterone receptor demonstrated increased expression upon exposure to the mutant form of ESR1. The increased expression of PR was found to be correlated with enhanced PR activity. To establish that ESR1^Y537S cells require PR for growth and dual ER-PR inhibition (i.e., complete hormone blockade) results in growth inhibition, an ex vivo organoid model was conducted using the rapidly proliferating, CDK4/6 inhibitor resistant WHIM20 cell line. Organoid data demonstrates that dual blockade of ER and PR via treatment with fulvestrant and onapristone results in growth inhibition in a cell model that is intended to mimic human disease.

Role of PR in ESR1 mutations

Source: Reprinted from Cancer Cell, Razavi et al, The Genomic Landscape of Endocrine-Resistant Advanced Breast Cancers, Copyright 2018. Reprinted with permission from British Journal of Cancer, Lopez-Knowles et al, Molecular characterisation of aromatase inhibitor-resistant advanced breast cancer: the phenotypic effect of ESR1 mutations, Copyright 2018. Reprinted with permission from Nature Springer.

Resistance to hormone-dependent gynecologic cancer

Gynecologic cancer overview

Ovarian and endometrial cancer represent the majority of gynecologic cancers. It is estimated that there are more than 22,000 new cases of ovarian cancer and 61,000 new cases of endometrial cancer annually, resulting in14,000 ovarian and 12,000 endometrial deaths in the United States (US) every year. As of 2019, it is estimated

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that there are 235,000 patients living with ovarian cancer and over 770,000 patients living with endometrial cancer in the US. By applying PR positivity (PR+) rates to the 2019 prevalence count, it is estimated that there are 300,000 patients with recurrent gynecologic cancer in the US, 130,000 of whom are PR+.

Maximal surgical debulking and platinum chemotherapy are the cornerstone treatments for primary gynecologic cancer. The aim of surgery is to confirm diagnosis, define extent of disease spread (staging), and resect all visible tumor tissue. The goal of cytoreductive surgery is removal of the entire tumor burden to achieve either complete removal of the tumor upon visual inspection (complete cytoreductive surgery) or a residual tumor of < 1 cm (optimal cytoreductive surgery). Even centers experienced in ovarian tumor cytoreductive surgery achieve optimal resection in only 50% of patients. Patients with incomplete/suboptimal cytoreductive surgery are at a significantly higher risk of recurrence and poor prognosis.

Following primary treatment for gynecologic cancer, the relapse rate is approximately 20-25% for early-stage disease and 70% for advanced (spread beyond primary site) disease. The survival curve after recurrence never plateaus, which means that the goal of treatment for recurrent gynecologic cancer is controlling the disease and disease-related symptoms, limiting treatment-related toxicity, and maintaining or improving quality of life. Primary or secondary resistance is the main cause for diminished effectiveness over time of platinum-based chemotherapy, contributing to the dismal outcome of advanced patients whose 5-year survival rate is less than 30%. Patients who are hormone receptor positive will often receive anti-estrogen therapy in the recurrent setting; however, anti-estrogen efficacy is modest in this setting. In general, treatment of recurrent disease is palliative and is initiated with the goals of controlling disease-related symptoms, limiting treatment-related toxicity, maintaining or improving quality of life, delaying time to progression, and prolonging survival.

Illustrative hormone-dependent gynecologic treatment landscape

Reasons Why Such a Therapy is Needed

Cytoreductive surgery followed by combination platinum and taxane chemotherapy is the first-line treatment for most gynecologic cancer patients regardless of type. Outside of DNA repair deficient high grade serous ovarian cancer, there are limited treatment options for all other forms of ovarian and endometrial cancer. Given the above-mentioned 5-year survival rate of less than 30%, there is a critical need to identify a targeted treatment in the recurrent setting. Ovarian and endometrial cancer remains a serious, life threatening, unmet medical need, resulting in more than 26,000 estimated deaths in the US every year.

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Preclinical data

PR in Endometrial Cancer

Progesterone receptor (PR)-targeted therapies are modestly active in patients with endometrial cancer, which may be attributed to an evolving understanding of the underlying molecular mechanisms of PR-targeted therapies for this disease. In the normal endometrium, estrogen drives proliferation of the endometrial glandular epithelium, whereas progesterone counteracts the effects of estrogen. Progesterone acts by binding to the PR and has a dual role through both genomic and nongenomic pathways. Anti-progestins such as onapristone have recently been shown to be efficacious in mouse models of uterine cancer, suggesting that PR blockade may be an effective approach for treating uterine cancer.

Role of PR in endometrial cancer

Source: Reprinted from Molecular Cancer Therapeutics, Huang et al, Inhibiting Nuclear Phospho-Progesterone Receptor Enhances Antitumor Activity of Onapristone in Uterine Cancer, Copyright 2017. Reprinted with permission from Elsevier.

Note: In vivo effect of onapristone, trametinib, and the combination of both drugs on tumor weight, number of tumor nodules, and body weight. Error bars indicate the SEM; *, P < 0.05.

It has been reported that mitogen-activated protein kinases (MAPK) play a dual role in PR subcellular trafficking and aid in the rapid nuclear association of PR via Serine 294 (S294) phosphorylation in response to growth factors and in response to ligand (i.e., progesterone). In Huang et al 2017, PR+ endometrial cancer cells were implanted in mice and upon tumor engraftment were treated with onapristone and/or trametinib, a MEK inhibitor. If progesterone receptor does coordinate endometrial cancer response through MAPK via MEK signaling, then the MEK inhibitor, trametinib, should be anticipated to enhance onapristone sensitivity through blocking the nuclear translocation of phosphorylated PR. The study demonstrates that PR+ endometrial xenografts are sensitive to both onapristone and trametinib alone, and exhibit synergy when combined, indicating a rationale to develop onapristone alone or in combination with a MEK inhibitor for PR+ endometrial cancer.

PR in Ovarian cancer

Progesterone and progesterone receptors (PR) are increasingly gaining attention for their emerging role as critical regulators of breast, ovarian, and endometrial cancer. Progesterone is a steroid hormone that is produced primarily by the corpus luteum in the ovaries during the second half of the menstrual cycle or luteal phase. Cyclical hormone exposure beginning at menarche and ending in menopause occurs monthly and regulates the growth and differentiation of specialized tissues within the reproductive tract and breast tissues. Until recently, little was known about the relative distribution of PR within the subtypes of ovarian tumors. In a cohort of 504 ovarian tumors, Diep et al (2013) reported that 35% of the tumors were progesterone receptor-positive (PR+) and that PR expression is associated with better outcomes, indicating a potential role for hormone therapy in PR+ ovarian cancer. Importantly, several subtypes were found to be highly enriched for PR. Retrospective studies evaluating the association of total PR expression and progression-free disease survival support the concept that subsets of PR+ ovarian tumors are highly sensitive to hormones and thus more likely to respond to endocrine therapy.

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Development of extended release formulation

Precedent Formulation – Onapristone IR (ONA-IR)

Onapristone was originally developed in an immediate release or “IR” form (onapristone IR; ONA-IR). ONA-IR was first evaluated as an oral contraceptive and was dosed up to 400 mg/day for periods of 7 days during single ovulatory cycles in healthy female subjects. Later, ONA-IR 100 mg/day was administered for periods exceeding 12 months in breast cancer studies. Discontinuation of ONA-IR development by the original sponsor, Schering AG, is thought to have been due to the observation of liver test abnormalities and the perceived risk of drug-induced liver injury (DILI) during a Phase 2 study of ONA-IR as first line therapy in breast cancer subjects. Liver test elevations were considered a concern for the planned contraception and benign gynecological indications (e.g., uterine fibroids, endometriosis). However, renewed interest in anti-progestin therapy for PR-positive malignancies has led to the consideration of new strategies for reducing potential hepatotoxic effects of onapristone.

In developing new strategies for anti-progestin use, one consideration is that mifepristone, ulipristal, telapristone, and onapristone all contain a 17-carbon steroid ring structure that is typical of steroids. Anti-progestins with steroidal cores often display significant cross-reactivity with closely related steroid receptors, namely, androgen receptor (AR), glucocorticoid receptor (GR), and mineralocorticoid receptor (MR). This functional overlap is partly responsible for the side effects linked with the steroidal drugs, which themselves carry a potential DILI risk. Because onapristone binds to GRs less efficiently than to PRs, one strategy to minimize liver test elevations was to seek a new onapristone formulation that yielded steady state pharmacokinetic (PK) parameters where: (a) C_max is lower than the C_max associated with ONA-IR 100mg QD (to target a reduced risk for LFT elevations); and (b) C_min is at least approximately equal to the C_min associated ONA-IR 100mg QD (to target at least equivalent, sustained suppression of PR activity). Various formulation strategies were evaluated and a 50mg, BID (twice-daily), extended release tablet (onapristone XR; ONA-XR) was selected to be the second-generation dosage form for the clinical evaluation of onapristone in PR-positive cancers.

Pharmacokinetic and Phase 1 safety data suggest improved tolerability profile

Source: Reprinted from Drug Safety, Lewis et al, Onapristone Extended Release: Safety Evaluation from Phase I–II Studies with an Emphasis on Hepatotoxicity, Copyright 2020. Reprinted with permission from Nature Springer.

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Novel Formulation – Onapristone XR

Pharmacokinetic (PK) parameters for ONA-IR 100mg QD and ONA-XR 50mg BID were previously evaluated within a dose escalation component of a Phase 1-2 clinical study in female subjects with endometrial carcinoma, breast cancer or ovarian cancer. This study (Cottu et al 2018) reported that ONA-XR showed “Clinical benefit with excellent tolerance”, while defining a recommended phase 2 dose level of ONA-XR of 50mg, BID. The PK dataset from this clinical study enabled a direct comparison between C_max and C_min for ONA-IR 100mg QD and ONA-XR 50mg BID. Steady-state pharmacokinetics of ONA were estimated using standard noncompartmental methods and the nonparametric superposition tool in Phoenix WinNonlin version 8.3 (Certara Inc., Princeton, NJ). These methods assume linear pharmacokinetics from the first dose to steady state. Dosing with ONA-XR 50mg BID resulted in a steady-state C_max almost 3 times lower than the C_max for ONA-IR 100mg QD, while the steady-state C_min for both formulations were similar: 829 ng/mL versus 790 ng/mL for ONA-IR versus ONA-XR, respectively. The findings of the Phase 1-2 PK and safety evaluation support that the recently developed, extended release form of onapristone appears to have achieved the PK goals of the formulation exercise.

Completed clinical trials

The initial IR formulation (ONA-IR), developed by Schering AG at various strengths, was dosed up to 400 mg/day in healthy volunteers and 100 mg/day for periods exceeding six months in oncology studies. Arno Therapeutics (Cranbury, NJ) subsequently developed onapristone extended release (“ONA-XR”) formulation and administered it in doses of 10, 20, 30, 40 and 50 mg ONA-XR BID for up to 52 weeks. We acquired ONA-XR from Arno Therapeutics. There are no associated future payments due to Arno.

Summary of clinical trials evaluating onapristone with IR or XR formulation

Note: BID: twice per day; DoR: duration of response; ORR: overall response rate; PFS: progression free survival.

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Onapristone IR Clinical Data

Across first and second line metastatic breast cancer, onapristone IR (ONA-IR) demonstrated clinical activity comparable to anti-estrogen standard of care. We believe that by selecting for PR+ status and combining ONA-XR, an improved form of ONA-IR, with anti-estrogen therapy to promote complete hormone blockade, we will potentially generate superior efficacy data compared to the current standard of care treatment options.

First Line Locally Advanced or Metastatic Breast Cancer

A Phase 2 study investigating onapristone (ONA-IR, 100 mg/day as a single daily dose) as first-line endocrine therapy in patients with breast cancer was conducted as an investigator-initiated study, as shown below. Nineteen patients, either with locally advanced breast cancer (n = 12) or who were elderly with primary breast cancer and considered unfit for standard of care (n = 7) received ONA-IR. In 17 of the 19 patients, tumors expressed ER while 12 of 18 tumors tested expressed PR.

Among 18 patients who were evaluable for response, 10 had a partial response and 2 had stable disease (“SD”) for six months or more. The median duration of objective response and SD was 70 weeks. Ten patients were ER-positive/PR-positive, of whom 7 achieved partial response (PR; tumor shrinkage of >30%) and 1 had SD. Overall, the clinical benefit rate was considered comparable to the current standard of care of letrozole (anti-estrogen) and palbociclib (CDK4/6 inhibitor).

Comparison of ONA-IR to standard of care in 1L locally advanced or metastatic breast cancer

Note: CBR: clinical benefit rate; LET: letrozole; ONA: onapristone, ORR: overall response rate; PAL: palbociclib.

Second Line Metastatic Breast Cancer

A non-randomized, open label, multicenter Phase 2 study was conducted at 13 sites in Germany and the United Kingdom, as shown below. The study goal was to investigate the efficacy and safety of ONA-IR when given 100 mg/day to post-menopausal women with advanced breast cancer who had progressed on tamoxifen, a selective estrogen receptor modulator therapy. The study was also designed to assess the influence of onapristone on the levels of relevant endocrine parameters (cortisol, androstenedione, estrone and estradiol).

Of the 101 evaluable patients, 1 had a complete response (“CR”), 9 had a partial response, and 39 had SD for three months or more. The median duration of response was 11 months. Median time to progression was 4 months.

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In second line metastatic breast cancer, ONA-IR exhibited monotherapy activity in patients who had progressed while on tamoxifen. In this trial, patients were not screened for progesterone receptor positive (PR+) status, meaning that only 60% of enrolled patients would have expected to be PR+ based upon historical prevalence in this setting and therefore derive clinical benefit from ONA-IR. Therefore, this trial potentially under-represents the likely true clinical benefit of ONA-IR had patients been stratified for the partial response biomarker. Despite administering a monotherapy without patient selection for PR+, ONA-IR demonstrated comparable clinical activity to standard of care anti-estrogens (FUL), CDK4/6 inhibitors (PAL), and the combination of the two (FUL + PAL).

Comparison of ONA-IR to standard of care in 2L metastatic breast cancer

Note: CBR: clinical benefit rate; FUL: fulvestrant; LET: letrozole; ONA: onapristone, ORR: overall response rate; PAL: palbociclib.

Onapristone XR Clinical Data

Overall, 128 subjects received at least a single dose of ONA-XR across both healthy volunteer and cancer trials through December 31, 2020. Multiple drug product formulations of onapristone have been developed for evaluation throughout the clinical development program. Clinical development was initiated with a 10 mg immediate release (IR) capsule. An IR tablet formulation (10mg, 25 mg) and extended release (XR) tablet formulation (2.5 mg, 5 mg, 10 mg, and 20 mg) were also developed. The tablets have been administered as a single tablet or in multiples in order to obtain the desired dosage. The XR tablet has been used in ongoing safety and efficacy studies.

Clinical studies incorporating new formulation

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Note: BID: twice per day; IR: immediate release; PK: pharmacokinetic; PR: progesterone receptor; QD: once per day; XR: extended release.

Thirty-one subjects (27%) of the total onapristone safety set (n = 128) experienced any treatment emergent adverse event (TEAE), as shown below. Adverse events were generally consistent across all defined groups. Thirteen subjects experienced Grade 3 or Grade 4 TEAEs that were deemed related to ONA-XR with no correlation across dosing groups. The most common drug-related TEAEs included an increase in gamma-glutamyltransferase in nine subjects (7%) and an increase in aspartate aminsotranferase in four subjects (3%). These events are generally consistent with prior anti-progestin experience, including onapristone. In addition, there were no clinically significant post-dose changes in electrocardiograms (ECGs), vital signs, or safety laboratory results.

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Treatment emergent adverse events (as of December 31, 2020)