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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 10-Q

(Mark One)

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For the transition period from ________ to ________

Commission File Number: 377-02943

PASSAGE BIO, INC.

(Exact Name of Registrant as Specified in its Charter)

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Registrant’s telephone number, including area code: (267) 866-0311

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ◻ No ⌧

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes ⌧ No ◻

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.

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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 pursuant to Section 13(a) of the Exchange Act. ◻

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ◻ No ⌧

Securities registered pursuant to Section 12(b) of the Act:

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As of May 8, 2020, the registrant had 45,350,687 shares of common stock, $0.0001 par value per share, outstanding.

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CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

This Quarterly Report on Form 10-Q contains forward-looking statements. All statements other than statements of historical facts contained in this Quarterly Report are forward-looking statements. In some cases, you can identify forward-looking statements by terms such as “may,” “will,” “should,” “expect,” “plan,” “anticipate,” “could,” “intend,” “target,” “project,” “contemplate,” “believe,” “estimate,” “predict,” “potential” or “continue” or the negative of these terms or other similar expressions, although not all forward-looking statements contain these words. All statements other than statements of historical fact contained in this Quarterly Report, including without limitation statements regarding our plans to develop and commercialize our product candidates, the timing of our ongoing or planned clinical trials, the timing of and our ability to obtain and maintain regulatory approvals, the clinical utility of our product candidates, our commercialization, marketing and manufacturing capabilities and strategy, our expectations about the willingness of healthcare professionals to use our product candidates, the sufficiency of our cash and cash equivalents, the expected impact of the COVID-19 pandemic on our operations, and the plans and objectives of management for future operations and capital expenditures are forward-looking statements.

The forward-looking statements in this Quarterly Report are only predictions and are based largely on our current expectations and projections about future events and financial trends that we believe may affect our business, financial condition and results of operations. These forward-looking statements speak only as of the date of this Quarterly Report and are subject to a number of known and unknown risks, uncertainties and assumptions, including those described under the sections in this Quarterly Report entitled “Risk Factors” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and elsewhere in this Quarterly Report.

Because forward-looking statements are inherently subject to risks and uncertainties, some of which cannot be predicted or quantified and some of which are beyond our control, you should not rely on these forward-looking statements as predictions of future events. The events and circumstances reflected in our forward-looking statements may not be achieved or occur and actual results could differ materially from those projected in the forward-looking statements. Moreover, we operate in an evolving environment. New risk factors and uncertainties may emerge from time to time, and it is not possible for management to predict all risk factors and uncertainties. Except as required by applicable law, we do not plan to publicly update or revise any forward-looking statements contained herein, whether as a result of any new information, future events, changed circumstances or otherwise. We intend the forward-looking statements contained in this Quarterly Report to be covered by the safe harbor provisions for forward-looking statements contained in Section 27A of the Securities Act of 1933, as amended, or the Securities Act, and Section 21E of the Securities Exchange Act of 1934, as amended, or the Exchange Act.

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PART I-FINANCIAL INFORMATION

Item 1. Financial Statements.

Passage Bio, Inc.

Balance Sheets

(Unaudited)

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See accompanying notes to unaudited interim financial statements.

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Passage Bio, Inc.

Statements of Operations

(Unaudited)

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See accompanying notes to unaudited interim financial statements.

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Passage Bio, Inc.

Statements of Convertible Preferred Stock and Stockholders’ Equity (Deficit) For the Three Months Ended March 31, 2020 and 2019

(in thousands, except share data)

(Unaudited)

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See accompanying notes to unaudited interim financial statements.

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Passage Bio, Inc.

Statements of Cash Flows

(Unaudited)

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See accompanying notes to unaudited interim financial statements.

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Passage Bio, Inc.

Notes to Unaudited Interim Financial Statements

1. Nature of Operations

Passage Bio, Inc. (the Company), a Delaware corporation incorporated in July 2017, is a genetic medicines company focused on advancing transformative therapies for rare monogenic central nervous system diseases. The Company has a strategic research collaboration with the Trustees of the University of Pennsylvania’s (Penn’s), Gene Therapy Program (GTP) that provides the Company with access to one of the premier research institutions in the world for the discovery and preclinical development of genetic medicine product candidates and exclusive rights to certain rare, monogenic central nervous system (CNS) indications. Under this collaboration, GTP conducts discovery and investigation new drug enabling preclinical activities and the Company conducts all clinical development, regulatory strategy, and commercialization activities under the agreement. The Company also has a collaboration agreement and a development services and clinical supply arrangement with Catalent Maryland, Inc. (Catalent) (formerly Paragon Bioservices, Inc.) for clinical scale manufacturing requirements.

2. Risks and Liquidity

The Company has incurred recurring losses and negative cash flows from operations since inception and had an accumulated deficit of $76.2 million as of March 31, 2020. The Company anticipates incurring additional losses until such time, if ever, that it can generate significant sales of its product candidates currently in development. Substantial additional capital will be needed by the Company to fund its operations and to develop its product candidates.

In March 2020, the Company closed its initial public offering (IPO) in which the Company issued and sold 13,798,900 shares of its common stock, which included shares sold pursuant to an option granted to the underwriters to purchase additional shares, at a public offering price of $18.00 per share for net proceeds of $227.5 million after deducting underwriting discounts, commissions and other offering expenses.

The Company’s operations have consisted primarily of organizing the Company, securing financing, developing licensed technology, performing research and conducting preclinical studies. The Company faces risks associated with early-stage biotechnology companies whose product candidates are in development. Product candidates currently under development will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval prior to commercialization. These efforts require significant amounts of additional capital for the Company to complete its research and development, achieve its research and development objectives, defend its intellectual property rights, and recruit and retain skilled personnel, and key members of management. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales.

The Company plans to seek additional funding through public or private equity offerings, debt financings, other collaborations, strategic alliances and licensing arrangements. The Company may not be able to obtain financing on acceptable terms, or at all, and the Company may not be able to enter into strategic alliances or other arrangements on favorable terms, or at all. The terms of any financing may adversely affect the holdings or the rights of the Company’s stockholders. If the Company is unable to obtain funding, the Company could be required to delay, reduce or eliminate research and development programs, product portfolio expansion or future commercialization efforts, which could adversely affect its business prospects.

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Passage Bio, Inc.

Notes to Unaudited Interim Financial Statements

3. Summary of Significant Accounting Policies

The Company’s complete summary of significant accounting policies can be found in “Note 3. Summary of Significant Accounting Policies” in the audited financial statements included in the Company’s prospectus filed with the SEC on February 27, 2020.

Basis of Presentation

The accompanying financial statements have been prepared in accordance with accounting principles generally accepted in the United States (GAAP). Any reference in these notes to applicable guidance is meant to refer to GAAP as found in the Accounting Standards Codification (ASC) and Accounting Standards Updates (ASU) promulgated by the Financial Accounting Standards Board (FASB).

Interim Financial Statements

The accompanying unaudited interim financial statements have been prepared from the books and records of the Company in accordance with GAAP for interim financial information and Rule 10-01 of Regulation S-X promulgated by the Securities and Exchange Commission (SEC), which permits reduced disclosures for interim periods. All adjustments, consisting only of normal recurring adjustments, necessary for a fair presentation of the accompanying balance sheets, statements of operations, convertible preferred stock and stockholders’ equity (deficit), and cash flows have been made. Although these interim financial statements do not include all of the information and footnotes required for complete annual financial statements, management believes the disclosures are adequate to make the information presented not misleading. Unaudited interim results of operations and cash flows are not necessarily indicative of the results that may be expected for the full year. Unaudited interim financial statements and footnotes should be read in conjunction with the December 31, 2019 financial statements and footnotes included in the prospectus as filed with the SEC on February 27, 2020.

Use of Estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and contingent liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Actual results could differ from those estimates.

Estimates and assumptions are periodically reviewed and the effects of the revisions are reflected in the accompanying financial statements in the period they are determined to be necessary. Prior to the IPO, significant areas that required management’s estimates included the fair value of the Company’s future tranche right liability and its common stock. After the IPO, the most significant judgements are used in estimates to determine the fair value of stock options issued.

Fair Value of Financial Instruments

Management believes that the carrying amounts of the Company’s financial instruments, including cash equivalents, prepaid expenses, and accounts payable, approximate fair value due to the short-term nature of those instruments. The future tranche right liability was recorded at its estimated fair value.

Share-based compensation

The Company measures share-based awards at their grant-date fair value and records compensation expense on a straight-line basis over the vesting period of the awards.

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Passage Bio, Inc.

Notes to Unaudited Interim Financial Statements

Estimating the fair value of share-based awards requires the input of subjective assumptions, including, prior to the IPO, the estimated fair value of the Company's common stock, and, for stock options, the expected life of the options and stock price volatility. The Company accounts for forfeitures for stock option awards as they occur. The Company uses the Black-Scholes option pricing model to value its stock option awards. The assumptions used in estimating the fair value of share-based awards represent management's estimate and involve inherent uncertainties and the application of management's judgment. As a result, if factors change and management uses different assumptions, share-based compensation expense could be materially different for future awards.

The expected life of the stock options is estimated using the "simplified method," as the Company has no historical information from which to develop reasonable expectations about future exercise patterns and post-vesting employment termination behavior for its stock option grants. The simplified method is the midpoint between the vesting period and the contractual term of the option. For stock price volatility, the Company uses comparable public companies as a basis for its expected volatility to calculate the fair value of option grants. The risk-free rate is based on the U.S. Treasury yield curve commensurate with the expected life of the option.

Net Loss Per Share

Basic net loss per share of common stock is computed by dividing net loss by the weighted-average number of shares of common stock outstanding during each period. Diluted loss per share of common stock includes the effect, if any, from the potential exercise or conversion of securities, such as convertible preferred stock, which would result in the issuance of incremental shares of common stock. For diluted net loss per share, the weighted-average number of shares of common stock is the same for basic net loss per share due to the fact that when a net loss exists, dilutive securities are not included in the calculation as the impact is anti-dilutive.

The following potentially dilutive securities have been excluded from the computation of diluted weighted-average shares of common stock outstanding, as they would be anti-dilutive:

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Amounts in the above table reflect the common stock equivalents.

Recently Issued Accounting Pronouncements

In February 2016, the FASB issued ASU No. 2016-02, Leases, which requires a lessee to record a right-of-use asset and a corresponding lease liability on the balance sheet for all leases with terms longer than 12 months. A modified retrospective transition approach is required for lessees for capital and operating leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements, with certain practical expedients available. As the Company has elected to use the extended transition period for complying with new or revised accounting standards as available under the Jobs Act, the standard is effective for the Company beginning January 1, 2021, with early adoption permitted. The Company is currently evaluating the expected impact that the standard could have on its financial statements and related disclosures.

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Passage Bio, Inc.

Notes to Unaudited Interim Financial Statements

4. Fair Value of Financial Instruments

Fair value is the price that could be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. Fair value determination in accordance with applicable accounting guidance requires that a number of significant judgments be made. Additionally, fair value is used on a nonrecurring basis to evaluate assets for impairment or as required for disclosure purposes by applicable accounting guidance on disclosures about fair value of financial instruments. Depending on the nature of the assets and liabilities, various valuation techniques and assumptions are used when estimating fair value. The carrying amounts of certain of the Company’s financial instruments, including prepaid expense and accounts payable are shown at cost, which approximates fair value due to the short-term nature of these instruments. The Company follows the provisions of FASB ASC Topic 820, Fair Value Measurement, for financial assets and liabilities measured on a recurring basis. The guidance requires fair value measurements be classified and disclosed in one of the following three categories:

The following fair value hierarchy table presents information about the Company’s assets measured at fair value on a recurring basis:

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The Company evaluated the future tranche right feature within the Series A-1 convertible preferred stock issued in 2018 and determined that the future tranche right was a freestanding financial instrument that was classified as a liability and was re-measured at each reporting period until the redemption feature was exercised in connection with the sale and issuance of the Series A-2 convertible preferred stock in May 2019.

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Passage Bio, Inc.

Notes to Unaudited Interim Financial Statements

5. Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consisted of the following:

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6. Commitments and Contingencies

Amended and Restated Research, Collaboration and License Arrangement with Penn

In May 2020, the Company amended and restated its research, collaboration and licensing agreement with Penn (the Penn Expansion Agreement) for research and development collaborations and exclusive license rights to patents for certain products and technologies, which supersedes the Company’s existing sponsored research, collaboration and licensing agreement with Penn, dated September 18, 2018, as amended. Under the Penn Expansion Agreement, the Company agreed to fund discovery research conducted by Penn for five years, beginning in May 2020, and will receive exclusive rights, subject to certain limitations, to technologies resulting from the discovery research for the Company’s products developed with GTP, such as novel capsids, toxicity reduction technologies and delivery and formulation improvements. This funding commitment is $5.0 million annually, with quarterly payments of $1.3 million. The Penn Expansion Agreement also increased the number of remaining options available to the Company to commence additional licensed programs for rare, monogenic CNS indications from six to eleven, and extended the option exercise window by three years. Accordingly, the window to exercise all eleven remaining options extends to May 2025. If the Company were to exercise any of these options, it would owe Penn a non-refundable upfront fee of $1.0 million per product indication.

Catalent Agreements

In June 2019, the Company entered into a collaboration agreement (the Catalent Collaboration Agreement) with Catalent. As part of the Catalent Collaboration Agreement, the Company paid Catalent an upfront fee for the commissioning, qualification, validation and equipping of a clean room suite (the Clean Room Suite). Subject to validation of the Clean Room Suite, which is expected to occur by the end of 2020, the Company will pay an annual fee for five years for the use of the Clean Room Suite and is also committed to minimum annual purchase commitments.

In April 2020, the Company entered into a development services and clinical supply agreement (the Manufacturing and Supply Agreement) with Catalent to secure clinical scale manufacturing capacity for batches of active pharmaceutical ingredients for the Company’s gene therapy product candidates. The Manufacturing and Supply Agreement confirms the terms contemplated by the Catalent Collaboration Agreement. The Catalent Collaboration Agreement continues to be in effect pursuant to its terms.

Under the terms of the Manufacturing and Supply Agreement, Catalent has agreed to manufacture batches of drug product for the Company’s gene therapy product candidates at the Clean Room Suite at a Catalent facility provided for in the Catalent Collaboration Agreement. The Manufacturing and Supply Agreement provides for a term of five years which period may be extended once, at the Company’s option, for an additional five year-period.

The Company has the right to terminate the Manufacturing and Supply Agreement for convenience or other reasons specified in the Manufacturing and Supply Agreement upon prior written notice. If the Company terminates the

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Passage Bio, Inc.

Notes to Unaudited Interim Financial Statements

Manufacturing and Supply Agreement for convenience and certain other specified events, it will be obligated to pay an early termination fee to Catalent.

Under both the Collaboration Agreement and the Manufacturing and Supply Agreement, the Company has an annual minimum commitment of $10.6 million per year owed to Catalent for five years, subject to certain inflationary adjustments.

Operating Leases

The Company leases office space in Philadelphia, Pennsylvania under a noncancelable lease (Existing Lease Agreement), as amended. The lease is classified as an operating lease and the Company recognizes rent expense on a straight-line basis over the lease term. The Company recognized rent expense of $36,000 and $51,000 during the three months ended March 31, 2020 and 2019, respectively, related to this lease. The future minimum lease payments under the Company’s Existing Lease Agreement as of March 31, 2020 is $0.2 million for the remainder of 2020.

In April 2020, the Company entered into a new lease agreement (New Lease Agreement) for larger office space in Philadelphia to accommodate the Company’s continued growth and serve as the new corporate headquarters. The New Lease Agreement is expected to commence in January 2021 and is expected to expire in November 2031. Upon signing the New Lease Agreement, the Company amended the Existing Lease Agreement such that the Existing Lease Agreement will terminate five days after the commencement of the New Lease Agreement with no further payments due under the Existing Lease Agreement. The Company has an option to extend the term of the New Lease Agreement by up to two five-year terms. The landlord also will provide the Company with a tenant improvement allowance of up to $2.8 million. The future minimum lease payments under the Company’s New Lease Agreement are as follows:

Employment Agreements

The Company has entered into employment agreements with key personnel providing for compensation and severance in certain circumstances, as described in the respective employment agreements.

Other Research and Development Arrangements

The Company enters into agreements with contract research organizations (CROs) to assist in the performance of research and development activities. Expenditures to CROs will represent a significant cost in clinical development for the Company. The Company could also enter into additional collaborative research, contract research, manufacturing, and supplier agreements in the future, which may require upfront payments and long-term commitments of cash.

Patent Infringement Claim

On February 18, 2020, the Company received a letter from Regenxbio Inc. (Regenx), which stated its view that the use of the Company’s AAVhu68 capsid infringes patent claims to which Regenx has an exclusive license and which expire in 2024. Regenx also stated that it has exclusive licenses to various pending patent applications regarding the use of AAV vectors administered via instar-cisterna magna injection, and that these applications may lead to issued claims that

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Passage Bio, Inc.

Notes to Unaudited Interim Financial Statements

Regenx believes may, if issued, cover the Company’s planned method of administration for the Company’s lead product candidates. The Company believes it has valid defenses to the issued claims set forth by Regenx relating to AAVhu68. Further, the prosecution of pending patent applications is highly uncertain, and it is unclear whether any patents will be issued from these pending Regenx patent applications at all, much less with claims that are relevant to the administration of the Company’s product candidates. Regenx also asked for information regarding the Company’s relationship with Dr. Wilson while he was serving as an advisor to Regenx. Regenx's letter also offers to discuss licensing the applicable patent portfolios from them. In April 2020, the Company responded to Regenx indicating that it does not believe it requires a license to any of the specified Regenx patents or patent applications at this time, and that it found that Dr. Wilson’s relationship with the Company was consistent with his obligations to Regenx. The Company will continue to monitor the situation and, if necessary, take appropriate actions, which may include responding to further correspondence from Regenx, and engaging in discussions with Regenx regarding their claims. If any such patents were enforceable and such claims were ultimately successful, the Company might require a license to continue to use and sell any product candidates using such AAV vector.

7. Convertible Preferred Stock and Common Stock

Initial Public Offering

In March 2020, the Company completed its IPO in which the Company sold 13,798,900 shares of its common stock, which included shares sold pursuant to an option granted to the underwriters to purchase additional shares, at a public offering price of $18.00 per share. The Company received net proceeds of $227.5 million after deducting underwriting discounts, commissions, and other offering expenses paid by the Company. In addition, immediately prior to the initial closing of the IPO on March 3, 2020, (i) all of the Company’s outstanding shares of convertible preferred stock converted into an aggregate of 26,803,777 shares of common stock and (ii) the Company filed an amended and restated certificate of incorporation to, among other things, increase the number of authorized shares of common stock to 300.0 million.

8. Share-Based Compensation

Equity Incentive Plan

The Company has two equity incentive plans: the 2018 Equity Incentive Plan, as amended, and the 2020 Equity Incentive Plan. New awards can only be granted under the 2020 Equity Incentive Plan (the Plan). The total number of shares authorized under the Plan as of March 31, 2020 was 5,362,823. Of this amount, 4,435,181 shares were available for future grants as of March 31, 2020. The number of shares of the Company’s common stock that may be issued pursuant to rights granted under the Plan shall automatically increase on January 1st of each year, commencing on January 1, 2021 and continuing for ten years, in an amount equal to five percent of the total number of shares of the Company’s common stock outstanding on December 31st of the preceding calendar year, subject to the discretion of the board of directors or compensation committee to determine a lesser number of shares shall be added for such year. The Plan provides for the granting of common stock, incentive stock options, nonqualified stock options, restricted stock awards, and/or stock appreciation rights to employees, directors, and other persons, as determined by the Company’s board of directors. The Company’s stock options vest based on the terms in each award agreement, generally over four-year periods, and have a term of ten years.

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Passage Bio, Inc.

Notes to Unaudited Interim Financial Statements

The Company measures share-based awards at their grant-date fair value and records compensation expense on a straight-line basis over the vesting period of the awards. The Company recorded share-based compensation expense in the following expense categories in its accompanying statements of operations for the period presented:

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During the three months ended March 31, 2020, the Company modified certain awards and recognized an additional $0.7 million related to the modifications, $0.6 million of which was recognized in research and development expense and $0.1 million was recognized in general and administrative expense.

The following table summarizes stock option activity for the three months ended March 31, 2020:

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The weighted-average grant date fair value of options granted was $9.93 and $0.73 for the three months ended March 31, 2020 and 2019, respectively. As of March 31, 2020, the total unrecognized compensation expense related to unvested stock option awards was $41.8 million, which the Company expects to recognize over a weighted-average period of 2.53 years.

The fair value of each option was estimated on the date of grant using the weighted average assumptions in the table below:

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The Plan provides certain holders of stock options an election to early exercise prior to vesting. The Company has the right to repurchase early exercised options without transferring any appreciation in the value of the underlying shares to the employee if the employee terminates employment before the end of the original vesting period. The repurchase price is the lesser of the original exercise price or the then fair value of the Company’s common stock. At March 31, 2020, $44,000 of proceeds from unvested early exercised options were recognized as a non-current liability in other liabilities in the accompanying balance sheet.

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Passage Bio, Inc.

Notes to Unaudited Interim Financial Statements

The 2018 Equity Incentive Plan allowed for the exercise of options to be financed with nonrecourse notes. For accounting purposes, payment of principal and interest are viewed as the exercise price of the option. Therefore, no interest income was recognized.

The following table summarizes activity relating to early exercises of stock options during the three months ended March 31, 2020:

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Nonrecourse Promissory Notes with Related Parties

In February 2019, the Company’s interim chief executive officer and chief operating officer elected to early exercise 688,875 and 309,994 stock options, respectively, in exchange for cash proceeds of $0.2 million and nonrecourse promissory notes (the Notes) of $0.8 million. The Notes bore interest at 2.91% and were secured by the underlying shares of common stock that were issued until January 2020, when the Company forgave the Notes and associated interest related to the early exercise of stock options by the interim chief executive officer and chief operating officer. An aggregate of 406,894 shares that were previously not considered outstanding for accounting purposes due to being secured by the Notes became outstanding upon the forgiveness of the Notes in January 2020.

Employee Stock Purchase Plan

The Company’s 2020 Employee Stock Purchase Plan (the ESPP) became effective on February 28, 2020. The ESPP authorizes the issuance of up to 434,000 shares of the Company’s common stock. The number of shares of the Company’s common stock that may be issued pursuant to rights granted under the ESPP shall automatically increase on January 1st of each year, commencing on January 1, 2021 and continuing for ten years, in an amount equal to one percent of the total number of shares of the Company’s common stock outstanding on December 31st of the preceding calendar year, subject to the discretion of the board of directors or compensation committee to determine a lesser number of shares shall be added for such year.

Under the ESPP, eligible employees can purchase the Company’s common stock through accumulated payroll deductions at such times as are established by the compensation committee. Eligible employees may purchase the Company’s common stock at 85% of the lower of the fair market value of the Company’s common stock on the first day of the offering period or on the last day of the offering period. Eligible employees may contribute up to 15% of their eligible compensation. Under the ESPP, a participant may not accrue rights to purchase more than $25,000 worth of the Company’s common stock for each calendar year in which such right is outstanding.

Effective March 3, 2020, employees who elected to participate in the ESPP commenced payroll withholdings that accumulate through November 15, 2020. In accordance with the guidance in ASC 718-50 – Compensation – Stock Compensation, the ability to purchase shares of the Company’s common stock at 85% of the lower of the price on the first day of the offering period or the last day of the offering period (i.e. the purchase date) represents an option and, therefore, the ESPP is a compensatory plan under this guidance. Accordingly, share-based compensation expense is determined based on the option’s grant-date fair value as estimated by applying the Black Scholes option-pricing model and is recognized over the withholding period. The Company recognized share-based compensation expense of $23,000 during the three months ended March 31, 2020 related to the ESPP.

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Passage Bio, Inc.

Notes to Unaudited Interim Financial Statements

9. Related-Party Transactions

Penn Agreement

Penn is a stockholder of the Company. Research and development expenses with Penn during the three months ended March 31, 2020 and 2019 were $7.7 million and $2.9 million, respectively. The Company made $12.6 million in cash payments to Penn during the three months ended March 31, 2020, and had a prepaid research and development asset of $10.7 million and $5.7 million as of March 31, 2020 and December 31, 2019, respectively, in the accompanying balance sheets.

Consulting Agreement

James M. Wilson, M.D., Ph.D., an employee of Penn and a stockholder of the Company, serves as the Company’s chief scientific advisor pursuant to a consulting agreement. The Company recognized $31,000 of expense related to these services during the three months ended March 31, 2020, including $6,000 of share-based compensation expense.

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10. Subsequent Events

Outside of the items disclosed in Note 6, there are no other subsequent events that warrant disclosure.

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Item 2. Management’s Discussion and Analysis of Financial Condition and Results of Operations.

You should read the following discussion of our financial condition and results of operations in conjunction with our financial statements and the related notes and other financial information included elsewhere in this Quarterly Report on Form 10-Q and our final prospectus filed with the Securities and Exchange Commission pursuant to Rule 424(b)(4) under the Securities Act of 1933, as amended, dated February 28, 2020, or the Prospectus. In addition to historical financial information, this discussion contains forward-looking statements based upon current expectations that involve risks and uncertainties, such as statements of our plans, objectives, expectations, intentions and belief. Our actual results could differ materially from those anticipated in these forward-looking statements as a result of various factors, including those set forth in the section titled “Risk Factors” under Part II, Item 1A below.

Overview and Pipeline

We are a genetic medicines company focused on developing transformative therapies for rare, monogenic central nervous system, or CNS, disorders with limited or no approved treatment options. Our vision is to become the premier genetic medicines company by developing and ultimately commercializing therapies that dramatically and positively transform the lives of patients suffering from these life-threatening disorders. To achieve our vision, we have assembled a world-class team whose members have decades of collective experience in genetic medicines and rare disease drug development and commercialization. The field of genetic medicine is rapidly expanding and we believe we have a differentiated approach to developing treatments for rare, monogenic CNS disorders that enables us to select and advance product candidates with a higher probability of technical and regulatory success. We have a strategic research collaboration with the Trustees of the University of Pennsylvania’s, or Penn’s, Gene Therapy Program, or GTP, headed by Dr. James Wilson, a leader in the genetic medicines field. We leverage our close working relationship with the Orphan Disease Center, or the ODC, at Penn to develop historical and prospective external data for each disease for use in building comparable patient profiles of participants in interventional trials. Through these collaborations we have assembled a deep portfolio of genetic medicine product candidates all of which we retain global rights to, the details of which are outlined in the below table:

(1) Program includes ongoing natural history study of infantile and juvenile GM1 gangliosidosis patients.

PBGM01 for the Treatment of GM1

We are currently developing PBGM01 for the treatment of GM1 gangliosidosis, or GM1, which utilizes a proprietary, next-generation AAVhu68 capsid to deliver to the brain and peripheral tissues a functional GLB1 gene encoding

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lysosomal acid beta-galactosidase, or b-gal, for infantile GM1. Currently, there are no disease-modifying therapies approved for the treatment of GM1. We believe PBGM01 could provide patients with significantly improved outcomes. In preclinical models, we have observed meaningful transduction of both the CNS and critical peripheral organs for GM1 patients using our ICM method of administration in combination with our next-generation AAVhu68 capsid. ICM, or intra-cisterna magna injection, involves an injection at the craniocervical junction. We expect to submit an IND in the second quarter of 2020, initiate a Phase 1/2 trial in the fourth quarter of 2020 and anticipate initial 30-day safety and biomarker data to be available late in the first half of 2021. We are currently funding a GM1 natural history study being conducted by the ODC to collect prospective data on clinical disease progression in infantile and juvenile GM1. This data will be used to construct natural history patient profiles for use as matched case controls for comparison to the profiles of treated participants in our planned Phase 1/2 clinical trial. In April 2020, the U.S. Food and Drug Administration, or the FDA, granted Orphan Drug Designation to PBGM01. This designation represents an important recognition of the dire need for an effective treatment option for those suffering from GM1, while granting us financial incentives to support clinical development and the potential for up to seven years of market exclusivity in the U.S. upon regulatory approval.

PBFT02 for the Treatment of FTD-GRN

We are currently developing PBFT02 for the treatment of frontotemporal dementia, of FTD, which utilizes an AAV1 capsid to deliver to the brain a functional granulin, or GRN, gene encoding progranulin, for the treatment of FTD caused by a deficiency of progranulin, or FTD-GRN. Currently, there are no disease-modifying therapies approved for the treatment of FTD-GRN. We believe PBFT02 may provide patients with significantly improved outcomes. In a non-human primate, or NHP model, we observed superior transduction results of the CNS using our ICM method of administration and an AAV1 capsid compared to other AAV capsids. We expect to submit an IND in the second half of 2020 and initiate a Phase 1/2 trial in the first half of 2021 and anticipate clinical data to be available in the second half of 2021.

PBKR03 for the Treatment of Krabbe disease

We are currently developing PBKR03, which utilizes a proprietary, next-generation AAVhu68 capsid to deliver to the brain and peripheral tissues a functional GALC gene encoding the hydrolytic enzyme galactosylceramidase, for infantile Krabbe disease. Currently, there are no disease-modifying therapies approved for the treatment of Krabbe disease. We believe PBKR03 may provide patients with significantly improved outcomes. In preclinical models, we have observed meaningful transduction of both the CNS and critical peripheral organs for Krabbe patients using our ICM method of administration in combination with our next-generation AAVhu68 capsid. We expect to submit an IND in the second half of 2020 and initiate a Phase 1/2 trial in the first half of 2021 and anticipate clinical data to be available in the second half of 2021.

Discovery Programs

We also have three programs in the discovery or candidate selection stage: PBML04 for metachromatic leukodystrophy, or MLD, PBAL05 for amyotrophic lateral sclerosis, or ALS, and PBCM06 for Charcot-Marie-Tooth Type 2A, or CMT2A. We also have eleven options available to us to license programs for rare, monogenic CNS indications, along with rights and licenses to new gene therapy technologies developed by Penn.

Business Overview

We were incorporated in July 2017 under the laws of the State of Delaware. Since inception, we have devoted substantially all of our resources to acquiring and developing product and technology rights, conducting research and development, organizing and staffing our company, business planning and raising capital. We have incurred recurring losses, the majority of which are attributable to research and development activities, and negative cash flows from operations. Historically, we have funded our operations through the sale of convertible preferred stock and then, in the first quarter of 2020, we closed our IPO and received net proceeds of $227.5 million. Our net loss was $17.6 million for the three months ended March 31, 2020. As of March 31, 2020, we had an accumulated deficit of $76.2 million. Our primary use of cash is to fund operating expenses, which consist primarily of research and development expenditures,

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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 marketing approval for any of our product candidates, we expect to incur significant commercialization expenses related to product manufacturing, marketing, sales and distribution. Furthermore, 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 expenditures on other research and development activities.

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 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.

As of March 31, 2020, we had cash and cash equivalents of $366.8 million. We expect our existing cash and cash equivalents will enable us to fund our operating expenses and capital expenditure requirements into the first quarter of 2023.

COVID-19 Impact

We are continuing to proactively monitor and assess the current coronavirus disease 2019, or COVID-19, global pandemic. Since early March we have activated a management team taskforce to assess the potential impact on our business that may result from this rapidly evolving crisis and to avoid any unnecessary potential delays to our programs. At this time, our lead programs and research activities remain on track. The safety and well-being of employees, patients and partners is our highest priority.

Financial Operations Overview

License Agreement

University of Pennsylvania

In May 2020, we entered into an amended and restated research, collaboration and licensing agreement, or the Penn Expansion Agreement, with Penn, for research and development collaborations and exclusive license rights to patents for certain products and technologies, which supersedes the Original Penn Agreement (as defined below). Under the Penn Expansion Agreement, we will fund discovery research conducted by Penn for five years, beginning in May 2020, and will receive exclusive rights, subject to certain limitations, to technologies resulting from the discovery program for Passage Bio products developed with GTP, such as novel capsids, toxicity reduction technologies and delivery and formulation improvements. Our funding commitment is $5.0 million a year for five years, with quarterly payments of $1.3 million. The Penn Expansion Agreement also increased the number of remaining options available to us to commence additional licensed programs for rare, monogenic CNS indications from six to eleven, and extended the option exercise window by three years. Accordingly, the window to exercise the eleven remaining options extends to May 2025. If we were to exercise any of these eleven options, we would owe Penn a non-refundable upfront fee of $1.0 million per product indication.

In September 2018, we entered into a sponsored research, collaboration and licensing agreement, or the Original Penn Agreement, with the Trustees of the University of Pennsylvania, or Penn, for preclinical research and development

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collaborations and exclusive license rights to patents for certain products and technologies. As part of the Original Penn Agreement, we agreed to fund certain preclinical development activities as described therein.

The Original Penn Agreement allows us to exercise options to obtain exclusive intellectual property rights for certain current and future products in specified indications for non-refundable upfront fees of $1.0 million per product indication. We have currently exercised options to license six product candidates from Penn.

The Original Penn Agreement requires that we make payments of up to $16.5 million per product candidate in aggregate upon the achievement of specific development milestone events by such licensed product for a first indication, reduced development milestone payments for the second and third indications and no development milestone payments for subsequent indications. In addition, on a product by product basis, we are obligated to make up to $55.0 million in sales milestone payments on each licensed product based on annual sales of the licensed product in excess of defined thresholds.

Upon successful commercialization of a product using the licensed technology, we are obligated to pay to Penn, on a licensed product-by-licensed product and country-by-country basis, tiered royalties (subject to customary reductions) in the mid-single digits on annual worldwide net sales of such licensed product. In addition, we are obligated to pay to Penn a percentage of sublicensing income, ranging from the mid-single digits to low double digits, for sublicenses under the Original Penn Agreement.

Collaboration and Manufacturing and Supply Agreements

Catalent

We have a collaboration agreement with Catalent Maryland, Inc. or Catalent (formerly Paragon Bioservices, Inc.), or the Catalent Collaboration Agreement. As part of the Catalent Collaboration Agreement, we paid Catalent an upfront fee for the commissioning, qualification, validation and equipping of a clean room suite. Subject to validation of the clean room suite, which is expected to occur by the end of 2020, we will pay an annual fee for five years for the use of the clean room suite.

In April 2020, we entered into a development services and clinical supply agreement, or the Manufacturing and Supply Agreement, with Catalent to secure clinical scale manufacturing capacity for batches of active pharmaceutical ingredients for our gene therapy product candidates. The Manufacturing and Supply Agreement provides for a term of five years which period may be extended once, at our option, for an additional five year-period. In consideration for the use of the clean room suite, we have agreed to a minimum amount of purchase commitments for each year in the term, subject to adjustments for inflation.

Components of Results of Operations

Research and Development and Acquired In-Process Research and Development

Research and development expenses consist primarily of costs incurred in connection with the discovery and development of our product candidates. These expenses include:

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We track outsourced development costs and other external research and development costs to specific product candidates on a program-by-program basis, such as expenses incurred under our collaboration with Penn, 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 share-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.

Costs incurred in obtaining technology licenses are charged to research and development expense as acquired in-process research and development if the technology licensed has not reached technological feasibility and has no alternative future use.

General and Administrative Expenses

General and administrative expense consists primarily of personnel expenses, including salaries, benefits and share-based compensation expense, for employees and consultants in executive, finance, accounting, legal, and human resource functions. General and administrative expense also includes corporate facility costs, including rent, utilities, depreciation and maintenance, not otherwise included in research and development expense, as well as legal fees related to intellectual property and corporate matters and fees for accounting and consulting services.

We expect that our general and administrative expense 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, lawyers 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 The Nasdaq Stock Market, LLC and the SEC, insurance and investor relations costs. If any of our current or future product candidates obtains U.S. regulatory approval, we expect that we would incur significantly increased expenses associated with building a sales and marketing team.

Change in Fair Value of Future Tranche Right Liability

Our Series A-1 convertible preferred stock issued in September 2018 included a future tranche participation right permitting investors to purchase 22,209,301 shares of Series A-2 convertible preferred stock at a fixed purchase price of $2.15 per share through December 31, 2019. The future tranche right was recorded at fair value using a Black-Scholes

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option pricing model and was re-measured at each reporting period until the redemption feature was exercised in May 2019, at which time the then estimated fair value was reclassified to convertible preferred stock.

Interest Income

Interest income consists of interest earned on our cash equivalents, which consists of a commercial money market account. We expect our interest income to increase due to our investment of cash received from our IPO.

Results of Operations

Comparison of the Three Months Ended March 31, 2020 and 2019

The following table sets forth our results of operations for the three months ended March 31, 2020 and 2019.

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Research and Development Expenses

Research and development expenses increased by $10.1 million to $13.1 million for the three months ended March 31, 2020 from $3.0 million for the three months ended March 31, 2019. The increase was primarily due to an increase of $4.8 million in research and development costs incurred with Penn in preparation for several IND filings as well as an increase in other research costs of $2.9 million as we prepare for our clinical trials to begin in the second half of 2020 and early 2021. We also had a $2.3 million increase in personnel-related costs and a $0.2 million increase in facility and other costs due to increases in employee headcount in the research and development function.

We track outsourced development, outsourced personnel costs and other external research and development costs of specific programs. We do not track our internal research and development costs on a program-by-program basis. Research and development expenses are summarized by program in the table below:

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General and Administrative Expenses

General and administrative expenses increased by $3.6 million to $4.8 million for the three months ended March 31, 2020 from $1.2 million for the three months ended March 31, 2019. The increase was primarily due to a $2.2 million

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increase in personnel-related and share-based compensation expense due to increases in employee headcount. Our professional fees and facility costs also increased by $0.6 million and $0.8 million, respectively, as we expanded our operations to support our research and development efforts.

Change in Fair Value of Future Tranche Right Liability

The change in fair value of our future tranche right liability related to our Series A-1 preferred stock was primarily due to the increase in the estimated fair value of our Series A-2 convertible preferred stock. The future tranche right liability was settled in May 2019.

Interest Income

We recognized interest income of $0.3 million during the three months ended March 31, 2020, primarily due to the investment of cash proceeds.

Liquidity and Capital Resources

Overview

From inception through December 31, 2019, we funded our operations through the sale of convertible preferred stock, receiving aggregate net proceeds of $222.1 million. Upon the completion of our IPO, we received net proceeds of $227.5 million. As of March 31, 2020, we had $366.8 million in cash and cash equivalents and had an accumulated deficit of $76.2 million. We expect our existing cash and cash equivalents will enable us to fund our operating expenses and capital expenditure requirements into the first quarter of 2023.

Funding Requirements

Our primary use of cash is to fund operating expenses, most significantly research and development expenditures. 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 operational needs and capital requirements for clinical trials, other research and development expenditures, and business development activities. We currently have no credit facility or committed sources of capital. Because of the numerous risks and uncertainties associated with the development and commercialization of our product candidates, we are unable to estimate the amounts of increased capital outlays and operating expenditures associated with our current and anticipated clinical studies.

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 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 drug 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:

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Net Cash Used in Operating Activities

During the three months ended March 31, 2020, we used $21.1 million of net cash in operating activities. Cash used in operating activities reflected a net loss of $17.6 million and a $5.9 million net increase in our operating assets and liabilities. The primary use of cash was to fund our operations related to the development of our product candidates. Cash used in these activities was partially offset by noncash charges of $2.4 million related to share-based compensation, deprecation and changes in deferred rent.

During the three months ended March 31, 2019, we used $0.2 million of net cash in operating activities. Cash used in operating activities reflected a net loss of $7.7 million. Cash used was partially offset by net decrease in our operating assets and liabilities of $3.3 million, noncash charges of $4.2 million, consisting of $3.5 million for the loss on the change in fair value of our future tranche right liability, $0.2 million in share-based compensation, and a $0.5 million change in our deferred rent balance.

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Net Cash Used in Investing Activities

During the three months ended March 31, 2020 and 2019, we used $0.1 million and $0.9 million, respectively, for the purchase of property and equipment.

Net Cash Provided by Financing Activities

During the three months ended March 31, 2020 and 2019, financing activities provided $229.9 million and $20.0 million, respectively, from the sale of our common stock and convertible preferred stock, respectively. During the three months ended March 31, 2019, we received $0.2 million from the exercise of stock options.

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 and Estimates

During the three months ended March 31, 2020, there were no material changes to our critical accounting policies and estimates from those described under the heading “Management’s Discussion and Analysis of Financial Condition and Results of Operations—Critical Accounting Policies and Estimates” in the Prospectus.

JOBS Act Accounting Election

We are an “emerging growth company,” as defined in the Jumpstart Our Business Startups Act of 2012, or the JOBS Act. Under the JOBS Act, emerging growth companies can delay adopting new or revised accounting standards issued subsequent to the enactment of the JOBS Act until such time as those standards apply to private companies.

We have elected to use this extended transition period for complying with new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date we (i) are no longer an emerging growth company or (ii) affirmatively and irrevocably opt out of the extended transition period provided in the JOBS Act. 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 will remain an emerging growth company until the earliest of (1) the last day of our first fiscal year (a) in which we have total annual gross revenues of at least $1.07 billion, or (b) in which we are deemed to be a large accelerated filer, which means the market value of our common stock that is held by non-affiliates exceeds $700.0 million as of the prior June 30^th, (2) the date on which we have issued more than $1.0 billion in non-convertible debt securities during the prior three-year period and (3) December 31, 2025.

Recent Accounting Pronouncements

See Note 2 to our interim financial statements included elsewhere in this Quarterly Report on Form 10-Q for a description of recent accounting pronouncements applicable to our financial statements.

Item 3. Quantitative and Qualitative Disclosures About Market Risk.

Not applicable.

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Item 4. Controls and Procedures.

Evaluation of Disclosure Controls and Procedures

As of March 31, 2020, management, with the participation of our Principal Executive Officer and Principal Financial and Accounting Officer, performed an evaluation of the effectiveness of the design and operation of our disclosure controls and procedures as defined in Rules 13a-15(e) and 15d-15(e) of the Securities Exchange Act of 1934, as amended, or the Exchange Act. Our disclosure controls and procedures are designed to ensure that information required to be disclosed in the reports we file or submit under the Exchange Act is recorded, processed, summarized, and reported within the time periods specified in the SEC’s rules and forms, and that such information is accumulated and communicated to our management, including the Principal Executive Officer and the Principal Financial and Accounting Officer, to allow timely decisions regarding required disclosures. Any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving the desired control objective and management necessarily applies its judgment in evaluating the cost-benefit relationship of possible controls and procedures. Based on this evaluation, our Principal Executive Officer and Principal Financial and Accounting Officer concluded that, as of March 31, 2020, the design and operation of our disclosure controls and procedures were effective at a reasonable assurance level.

Changes in Internal Control over Financial Reporting

Management determined that, as of March 31, 2020, there were no changes in our internal control over financial reporting that occurred during the fiscal quarter then ended that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.

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PART II-OTHER INFORMATION

Item 1. Legal Proceedings.

From time to time, we may be involved in legal proceedings arising in the ordinary course of our business. We are not presently a party to any legal proceedings that, in the opinion of management, would have a material adverse effect on our business. Regardless of outcome, litigation can have an adverse impact on us due to defense and settlement costs, diversion of management resources, negative publicity and reputational harm, and other factors.

Item 1A. Risk Factors.

Investing in our common stock involves a high degree of risk. Before making your decision to invest in shares of our common stock, you should carefully consider the risks and uncertainties described below, together with the other information contained in this quarterly report, including our financial statements and the related notes and “Management’s Discussion and Analysis of Financial Condition and Results of Operations”. The risks and uncertainties described below are not the only ones we face. Additional risks and uncertainties that we are unaware of, or that we currently believe are not material, may also become important factors that affect us. We cannot assure you that any of the events discussed below will not occur. These events could have a material and adverse impact on our business, financial condition, results of operations and prospects. If that were to happen, the trading price of our common stock could decline, and you could lose all or part of your investment.

Risks Related to Our Financial Position and Need for Additional Capital

We are a preclinical stage biotechnology company with a history of operating losses, and we may not achieve or sustain profitability. We anticipate that we will continue to incur losses for the foreseeable future. Our limited operating history may make it difficult for you to evaluate the success of our business to date and to assess our future viability.

We are a preclinical stage genetic medicines company with a limited operating history on which to base your investment decision. Biotechnology product development is a highly speculative undertaking and involves a substantial degree of risk. Our operations to date have been limited primarily to organizing and staffing our company, business planning, raising capital and entering into collaboration agreements for conducting preclinical research and development activities for our product candidates. All of our lead product candidates are still in the preclinical testing stage. We have no products in clinical development or approved for commercial sale and have not generated any revenue from commercial product sales, and we will continue to incur significant research and development and other expenses related to our clinical development and ongoing operations. We have funded our operations to date through proceeds from sales of our convertible preferred stock, and the completion of our initial public offering, or IPO, and do not expect to receive revenue for many years, if ever.

We have incurred net losses since our inception in 2017. We incurred net losses of $17.6 million and $45.6 million for the three months ended March 31, 2020 and the year ended December 31, 2019, respectively. As of March 31, 2020, we had an accumulated deficit of $76.2 million. Substantially all of our operating losses have resulted from costs incurred in connection with our research and development programs and from general and administrative costs associated with our operations. We expect to continue to incur significant expenses and operating losses over the next several years and for the foreseeable future as we intend to continue to conduct research and development, clinical testing, regulatory compliance activities, manufacturing activities, and, if any of our product candidates is approved, sales and marketing activities that, together with anticipated general and administrative expenses, will likely result in us incurring significant losses for the foreseeable future. Our prior losses, combined with expected future losses, have had and will continue to have an adverse effect on our stockholders’ deficit and working capital.

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We expect that it will be several years, if ever, before we have a commercialized product. We anticipate that our expenses will increase substantially if, and as, we:

In addition, as a new business, we may encounter unforeseen expenses, difficulties, complications, delays and other known and unknown factors. We expect to transition rapidly from a small start-up company with a focus on hiring employees, establishing key collaborations and financing to a more fully-integrated company that is capable of supporting clinical development, manufacturing and commercial activities. We may not be successful in such a transition.

We have never generated revenue from product sales and may never achieve or maintain profitability.

We have no products in clinical development or approved for commercial sale and have not generated any revenue from commercial product sales. To become and remain profitable, we must develop and eventually commercialize product candidates with significant market potential, which will require us to be successful in a range of challenging activities. These activities can include completing preclinical studies and initiating and completing clinical trials of our product candidates, obtaining marketing approval for these product candidates, manufacturing, marketing and selling those products that are approved and satisfying any post marketing requirements. We may never succeed in any or all of these activities and, even if we do, we may never generate revenues that are significant or large enough to achieve profitability. Because of the numerous risks and uncertainties associated with pharmaceutical product development, we are unable to accurately predict the timing or amount of increased expenses or when, or if, we will be able to achieve profitability.

Even if we do achieve profitability, we may not be able to sustain or increase profitability on a quarterly or annual basis. Our failure to become and remain profitable would decrease the value of our company and could impair our ability to raise capital, maintain our research and development efforts, expand our business or continue our operations. A decline in the value of our company also could cause you to lose all or part of your investment.

We will need to raise additional funding before we can expect to become profitable from any potential future sales of our products. This additional financing may not be available on acceptable terms, or at all. Failure to obtain this necessary capital when needed may force us to delay, limit, or terminate our product development efforts or other operations.

We will require substantial future capital in order to complete planned and future preclinical and clinical development for PBGM01, PBFT02, PBKR03 and any other product candidates, if any, and potentially commercialize these product candidates, if approved. We expect our spending levels to significantly increase in connection with our preclinical studies and planned clinical trials, if any, of our lead product candidates. In addition, if we obtain marketing approval for any of our product candidates, we expect to incur significant expenses related to product sales, medical affairs, marketing, manufacturing and distribution. Furthermore, we expect to incur additional costs associated with operating as a public company. Accordingly, we will need to obtain substantial additional funding in connection with our continuing

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operations. If we are unable to raise capital when needed or on acceptable terms, we would be forced to delay, reduce or eliminate certain of our licensing activities, our research and development programs or other operations.

Our operations have consumed significant amounts of cash since inception. As of March 31, 2020, our cash and cash equivalents were $366.8 million. We expect that our existing cash and cash equivalents will enable us to fund our operating expenses and capital expenditure requirements into the first quarter of 2023. However, we have based this estimate on assumptions that may prove to be wrong, and our operating plan may change as a result of factors currently unknown to us. As a result, we could deplete our capital resources sooner than we currently expect.

Our future capital requirements will depend on many factors, including:

Accordingly, we will need to continue to rely on additional financing to achieve our business objectives, which may not be available to us on acceptable terms, or at all. We may seek additional capital due to favorable market conditions or strategic considerations, even if we believe we have sufficient funds for our current or future operating plans. If adequate funds are not available to us on a timely basis or on terms acceptable to us, we may be required to delay, limit, reduce or terminate preclinical studies, clinical trials or other development activities for one or more product candidates or discovery stage programs or delay, limit, reduce or terminate our establishment of sales and marketing capabilities or other activities that may be necessary to commercialize any product candidates, if approved.

Raising additional capital may cause dilution to our stockholders, 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 offerings, debt financings, collaborations, strategic alliances and marketing, distribution or licensing arrangements. We do not have any committed external source of funds. To the extent that we raise additional capital through the sale of equity or securities convertible into equity, 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

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limiting or restricting our ability to take specific actions, such as incurring additional debt, selling or licensing our assets, making 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 when needed or on terms acceptable to us, we may be required to delay, limit, reduce or terminate our 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.

Risks Related to Product Development and Regulatory Approval

The outbreak of the novel strain of coronavirus, SARS-CoV-2, which causes COVID-19, could adversely impact our business, including our preclinical development activities and planned clinical trials.

Public health crises such as pandemics or similar outbreaks could adversely impact our business. In December 2019, a novel strain of coronavirus, SARS-CoV-2, which causes COVID-19, surfaced in Wuhan, China. Since then, COVID-19 has spread to multiple countries, including the United States. As a result of the COVID-19 outbreak, or similar pandemics, we may experience disruptions that could severely impact our business, manufacturing, preclinical development activities, preclinical studies and planned clinical trials, including:

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These and other factors arising from the COVID-19 pandemic could worsen in countries that are already afflicted with COVID-19, could continue to spread to additional countries, or could return to countries where the pandemic has been partially contained, each of which could further adversely impact our ability to conduct preclinical development activities, preclinical studies and planned clinical trials and our business generally, and could have a material adverse impact on our operations and financial condition and results.

In addition, the trading prices for our common stock and other biopharmaceutical companies, as well as the broader equity and debt markets, have been highly volatile as a result of the COVID-19 pandemic and the resulting impact on economic activity. As a result, we may face difficulties raising capital when needed, and any such sales may be on unfavorable terms to us. Further, to the extent we raise additional capital through the sale of equity or convertible debt securities, the ownership interest of existing stockholders will be diluted.

The COVID-19 outbreak continues to rapidly evolve. The extent to which the outbreak may impact our business, manufacturing, preclinical development activities, preclinical studies and planned clinical trials will depend on future developments, which are highly uncertain and cannot be predicted with confidence. Such developments include the ultimate geographic spread of COVID-19, the duration of the outbreak, travel restrictions and actions to contain the outbreak or treat its impact, such as social distancing and quarantines or lock-downs in the United States and other countries, business closures or business disruptions and the effectiveness of actions taken in the United States and other countries to contain and treat the disease.

We are very early in our development efforts. Our business is dependent on our ability to advance our current and future product candidates through preclinical studies and clinical trials, obtain marketing approval and ultimately commercialize them. If we are unable, or experience significant delays in doing so, our business will be materially harmed.

We are very early in our development efforts and all of our product candidates are still in preclinical development. Additionally, we have a portfolio of programs that are in earlier stages of preclinical development and may never advance to clinical-stage development. Our ability to generate product revenue, which we do not expect will occur for many years, if ever, will depend heavily on the successful development and eventual commercialization of our product candidates, which may never occur. We currently generate no revenue from sales of any product and we may never be able to develop or commercialize a marketable product.

Each of our programs and product candidates will require additional preclinical and/or clinical development, regulatory approval in multiple jurisdictions, obtaining manufacturing supply, capacity and expertise, building a commercial organization or successfully outsourcing commercialization, substantial investment and significant marketing efforts before we generate any revenue from product sales. Our product candidates must be authorized for marketing by the U.S. Food and Drug Administration, or the FDA, or certain other ex-U.S. regulatory agencies before we may commercialize our product candidates.

The clinical and commercial success of our product candidates will depend on several factors, including the following:

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If we do not succeed in one or more of these factors in a timely manner or at all, we could experience significant delays or an inability to successfully commercialize our product candidates, which would materially harm our business. If we are unable to advance our product candidates to clinical development, obtain regulatory approval and ultimately commercialize our product candidates, or experience significant delays in doing so, our business will be materially harmed.

Preclinical and clinical development involve a lengthy and expensive process with an uncertain outcome. We may incur additional costs or experience delays in completing, or ultimately be unable to complete, the development and commercialization of our current product candidates or any future product candidates.

All of our product candidates are in preclinical development and their risk of failure is high. We currently rely exclusively on GTP for our preclinical and IND-enabling studies. It is impossible to predict when or if any of our product candidates will receive regulatory approval. To obtain the requisite regulatory approvals to commercialize any product candidates, we must demonstrate through extensive preclinical studies and lengthy, complex and expensive clinical trials that our product candidates are safe and effective in humans. Clinical testing can take many years to complete, and its outcome is inherently uncertain. We will rely on CROs for the clinical development of our lead candidates. Failure can occur at any time during the clinical trial process. The results of preclinical studies and early clinical trials or early cohorts of our clinical trials of our product candidates may not be predictive of the results of later-stage clinical trials or later cohorts of our clinical trials. Early clinical trials and in particular initial cohorts of early clinical trials often enroll significantly fewer patients than later stage clinical trials or later cohorts of the same clinical trial and may not be as predictive as larger trials. We may be unable to establish clinical endpoints that applicable regulatory authorities would consider clinically meaningful, and a clinical trial can fail at any stage of testing.

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Differences in trial design between early-stage clinical trials and later-stage clinical trials make it difficult to extrapolate the results of earlier clinical trials to later clinical trials. Moreover, clinical data are often susceptible to varying interpretations and analyses, and many companies that have believed their product candidates performed satisfactorily in clinical trials have nonetheless failed to obtain marketing approval of their products. A number of companies in the biotechnology industry have suffered significant setbacks in advanced clinical trials due to lack of efficacy or to unfavorable safety profiles, notwithstanding promising results in earlier trials. There is typically a high rate of failure of product candidates proceeding through clinical trials. Most product candidates that commence clinical trials are never approved as products and there can be no assurance that any of our future clinical trials will ultimately be successful or support clinical development of our current or any of our future product candidates.

We or our collaborators may experience delays in initiating or completing clinical trials. We or our collaborators also may experience numerous unforeseen events during, or as a result of, any future clinical trials that we could conduct that could delay or prevent our ability to receive marketing approval or commercialize our lead product candidates or any future product candidates, including:

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Patient enrollment, a significant factor in the timing of clinical trials, is affected by many factors including the size and nature of the patient population, the number and location of clinical sites we enroll, the proximity of patients to clinical sites, the eligibility and exclusion criteria for the trial, the design of the clinical trial, the inability to obtain and maintain patient consents, the risk that enrolled participants will drop out before completion, competing clinical trials and clinicians’ and patients’ perceptions as to the potential advantages of the product candidate being studied in relation to other available therapies, including any new drugs or therapeutic biologics that may be approved for the indications being investigated by us. Furthermore, we expect to rely on our collaborators, CROs and clinical trial sites to ensure the proper and timely conduct of our future clinical trials, including the patient enrollment process, and we have limited influence over their performance. Additionally, we could encounter delays if treating physicians encounter unresolved ethical issues associated with enrolling patients in future clinical trials of our product candidates in lieu of prescribing existing treatments that have established safety and efficacy profiles.

We could also encounter delays if a clinical trial is suspended or terminated by us, the IRBs of the institutions in which such trials are being conducted, or the FDA or other regulatory authorities, or if a clinical trial is recommended for suspension or termination by the Data Safety Monitoring Board for such trial. A suspension or termination may be imposed 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 or treatment, failure to establish or achieve clinically meaningful trial endpoints, changes in governmental regulations or administrative actions or lack of adequate funding to continue the clinical trial. Clinical studies may also be delayed or terminated as a result of ambiguous or negative interim results. Many of the factors that cause, or lead to, a delay in the commencement or completion of clinical trials may also ultimately lead to the denial of regulatory approval of our product candidates. Further, the FDA or other regulatory authorities may disagree with our clinical trial design and our interpretation of data from clinical trials, or may change the requirements for approval even after they have reviewed and commented on the design for our clinical trials.

Our product development costs will increase if we experience delays in clinical testing or marketing approvals. We do not know whether any of our clinical trials will begin as planned, will need to be restructured or will be completed on schedule, or at all. Significant clinical trial delays also could shorten any periods during which we may have the exclusive right to commercialize our product candidates and may allow our competitors to bring products to market before we do, potentially impairing our ability to successfully commercialize our product candidates and harming our business and results of operations. Any delays in our clinical development programs may harm our business, financial condition and results of operations significantly.

We have not tested any of our product candidates in clinical trials. Success in early preclinical studies or clinical trials may not be indicative of results obtained in later preclinical studies and clinical trials.

All of our product candidates are in the preclinical discovery stage. Conducting preclinical testing is a lengthy, time-consuming and expensive process. The length of time of such testing may vary substantially according to the type, complexity and novelty of the program, and often can be several years or more per program. Delays associated with programs for which we are conducting preclinical testing and studies may cause us to incur additional operating expenses. Though gene therapy product candidates like ours have been evaluated by others in clinical trials, our product candidates have never been evaluated in human clinical trials, and we may experience unexpected or adverse results in the future. We will be required to demonstrate through adequate and well-controlled clinical trials that our product candidates are safe and effective, with a favorable benefit-risk profile, for use in their target indications before we can seek regulatory approvals for their commercial sale. Our initial clinical trials will begin with relatively small cohorts before expanding in size in subsequent cohorts. If safety issues arise in an early cohort, we may be delayed or prevented from subsequently expanding into larger trial cohorts. Earlier gene therapy clinical trials conducted by others also utilized adeno-associated viral, or AAV, vectors. However, these studies should not be relied upon as evidence that our planned clinical trials will succeed. Trial designs and results from previous trials are not necessarily predictive of our future clinical trial designs or results, and initial positive results we may observe may not be confirmed upon full

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analysis of the complete trial data. In addition, the positive results we have observed for our product candidates in preclinical animal models may not be predictive of our future clinical trials in humans. Our product candidates may also fail to show the desired safety and efficacy in later stages of clinical development even if they successfully advance through initial clinical trials.

Interim “top-line” and preliminary data from our clinical trials that we or our partners 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 make public interim topline or preliminary data from our clinical trials. 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 topline data also remain subject to audit and verification procedures that may result in the final data being materially different from the preliminary or topline data that were previously made public. As a result, interim and preliminary data should be viewed with caution until the final data are available. Adverse differences between interim or preliminary or topline data and final data could significantly harm our reputation and business prospects.

If we do not achieve our projected development goals in the time frames we announce and expect, the commercialization of our products may be delayed.

From time to time, we estimate the timing of the accomplishment of various scientific, clinical, regulatory, manufacturing and other product development goals, which we sometimes refer to as milestones. These milestones may include the commencement or completion of preclinical studies and clinical trials and the submission of regulatory filings, including IND submissions. From time to time, we may publicly announce the expected timing of some of these milestones. All of these milestones are, and will be, based on a variety of assumptions. The actual timing of these milestones can vary significantly compared to our estimates, in some cases for reasons beyond our control. We may experience numerous unforeseen events during, or as a result of, any future clinical trials that we conduct that could delay or prevent our ability to receive marketing approval or commercialize our product candidates.

Gene therapy is a novel technology, which makes it difficult to predict the time and cost of product candidate development and subsequently obtaining regulatory approval. Currently, only a limited number of gene therapy products have been approved in the United States and in foreign countries.

Our current product candidates are based on gene therapy technology and our future success depends on the successful development of this novel therapeutic approach. The regulatory requirements that govern any novel gene therapy product candidates we develop are not entirely clear and are subject to change. The clinical study requirements of the FDA and ex-U.S. regulatory agencies and the criteria these regulators use to determine the safety and efficacy of a product candidate vary substantially according to the type, complexity, novelty and intended use and market of the potential products. The regulatory approval process for novel product candidates such as ours can be more expensive and take longer than for other, better known or extensively studied product candidates. Further, as we are developing novel treatments for diseases in which there is little clinical experience with new endpoints and methodologies, there is heightened risk that the FDA or comparable foreign regulatory bodies may not consider the clinical trial endpoints to provide clinically meaningful results, and the resulting clinical data and results may be more difficult to analyze. To date, only a limited number of gene therapy products have been approved in the United States and foreign countries, which makes it difficult to determine how long it will take or how much it will cost to obtain regulatory approvals for our product candidates in the United States or other jurisdictions. Further, approvals by an ex-U.S. regulatory agency may not be indicative of what the FDA may require for approval, or vice versa.

Our product candidates may cause undesirable and unforeseen side effects, which could delay or prevent their advancement into clinical trials or regulatory approval, limit the commercial potential or result in significant negative consequences.

While new AAV vectors have been developed to reduce side effects previously reported in third-party gene therapy treatments, gene therapy is still a relatively new approach to disease treatment and additional adverse side effects could

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develop. There also is the potential risk of delayed adverse events following exposure to gene therapy products due to persistent biologic activity of the genetic material or other components of products used to carry the genetic material.

Possible adverse side effects that could occur with treatment with gene therapy products include an immunologic reaction early after administration which, while not necessarily adverse to the patient’s health, could substantially limit the effectiveness of the treatment. For example, in previous third-party clinical trials involving AAV vectors for gene therapy, some subjects experienced the development of a T-cell antibody response, whereby after the vector is within the target cells, the cellular immune response system triggers the removal of transduced cells by activated T-cells. Further, following administration of any AAV vector, patients are likely to develop neutralizing antibodies specific to the vector administered. Other preclinical studies have suggested that high dosages of AAV administration may result in toxicity due to degeneration of the dorsal root ganglia. Preliminary results of our NHP toxicology studies for our PBGM01 and PBFT02 product candidates have demonstrated trigeminal ganglia and dorsal root ganglia toxicity. Based on these results, and if our vectors demonstrate a similar effect in other programs, we may decide or be required to perform additional preclinical studies or to halt or delay further clinical development of our product candidates.

In addition to side effects caused by the product candidate, the administration process or related procedures also can cause adverse side effects. Each of our lead product candidates are expected to be administered by injection into the ICM. While this method of administration has been available for decades, its use for therapies is relatively new, no therapies are currently approved using ICM administration, and it may be perceived as having greater risk than more common methods of administration, such as intravenous injection. If any such adverse events occur, our clinical trials could be suspended or terminated. If we cannot demonstrate that any adverse events were not caused by the drug or administration process or related procedures, the FDA or ex-U.S. regulatory authorities could order us to cease further development of, or deny approval of, our product candidates for any or all targeted indications. Even if we are able to demonstrate that all future serious adverse events are not product-related, such occurrences could affect patient recruitment or the ability of enrolled patients to complete the trial. Moreover, if we elect, or are required, to not initiate, delay, suspend or terminate any future clinical trial of any of our product candidates, the commercial prospects of such product candidates may be harmed and our ability to generate product revenues from any of these product candidates may be delayed or eliminated. Any of these occurrences may harm our ability to develop other product candidates, and may harm our business, financial condition and prospects significantly.

Additionally, if any of our product candidates receives marketing approval, the FDA could require us to adopt a Risk Evaluation and Mitigation Strategies, or REMS, to ensure that the benefits of the product outweigh its risks, which may include, among other things, a Medication Guide outlining the risks of the product for distribution to patients and a communication plan to health care practitioners. Furthermore, if we or others later identify undesirable side effects caused by our product candidate, several potentially significant negative consequences could result, including:

Any of these occurrences may harm our business, financial condition and prospects significantly.

Adverse public perception of genetic medicines may negatively impact regulatory approval of, and/or demand for, our potential products.

Regulatory approval of and/or demand for our potential products will depend in part on public acceptance of the use of genetic medicine for the prevention or treatment of human diseases. Public attitudes may be influenced by claims that genetic medicines are unsafe, unethical or immoral, and consequently, our products may not gain the acceptance of the

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public or the medical community. Adverse public attitudes may adversely impact our ability to enroll clinical trials. Moreover, our success will depend upon physicians prescribing, and their patients being willing to receive, treatments that involve the use of product candidates we may develop.

There have been several significant adverse side effects reported in genetic medicine treatments in the past. For example, in 1999, there was public backlash against gene therapy following the death of a clinical trial subject in a gene therapy clinical trial that utilized an adenovirus vector. It was later discovered that adenoviruses could generate an extreme immune system reaction that can be life-threatening. Dr. Wilson, our Chief Scientific Advisor, was a co-investigator of the 1999 trial while he was Director of the Institute for Human Gene Therapy of Penn. Serious adverse events in our clinical trials, or other clinical trials involving gene therapy by us or our competitors, even if not ultimately attributable to the relevant product candidates, and the resulting publicity, could result in increased government regulation, unfavorable public perception and potential regulatory delays in the clinical testing or approval of our product candidates.

As an organization, we have limited experience designing and no experience implementing clinical trials and we have never conducted pivotal clinical trials. Failure to adequately design a trial, or incorrect assumptions about the design of the trial, could adversely affect the ability to initiate the trial, enroll patients, complete the trial, or obtain regulatory approval on the basis of the trial results, as well as lead to increased or unexpected costs.

The design and implementation of clinical trials is a complex process. As an organization, we have limited experience designing and no experience implementing clinical trials, and we may not successfully or cost-effectively design and implement clinical trials that achieve our desired clinical endpoints efficiently, or at all. A clinical trial that is not well designed may delay or even prevent initiation of the trial, can lead to increased difficulty in enrolling patients, may make it more difficult to obtain regulatory approval for the product candidate on the basis of the study results, or, even if a product candidate is approved, could make it more difficult to commercialize the product successfully or obtain reimbursement from third-party payors. Additionally, a trial that is not well-designed could be inefficient or more expensive than it otherwise would have been, or we may incorrectly estimate the costs to implement the clinical trial, which could lead to a shortfall in funding.

The disorders we seek to treat have low prevalence and it may be difficult to identify patients with these disorders, which may lead to delays in enrollment for our trials or slower commercial revenue if approved.

Genetically defined disorders generally, and especially those for which our current product candidates are targeted, have low incidence and prevalence. For example, we estimate incidence of infantile GM1 is approximately 1.4 in 100,000 live births, that the incidence of Krabbe disease is approximately 2.6 in 100,000 births and that there are approximately 3,000 to 6,000 people in the United States with FTD-GRN. While certain states currently have mandatory newborn genetic screening for Krabbe disease, there is no mandatory screening for GM1. Without mandatory screening, it may be difficult for us to identify a sufficient number of eligible patients to conduct our clinical trials. These could be significant obstacles to the timely recruitment and enrollment of a sufficient number of eligible patients into our trials. Further, we expect to rely in part on our relationships with the Orphan Disease Center and other patient advocacy groups to assist in identifying eligible patients, and any deterioration of those relationships could impede our ability to successfully enroll patients. Patient enrollment may be affected by other factors including:

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Our inability to enroll a sufficient number of patients with these diseases for our planned clinical trials would result in significant delays and could require us to not initiate or abandon one or more clinical trials altogether. Enrollment delays in our clinical trials may result in increased development costs for our product candidates, which would cause the value of our company to decline and limit our ability to obtain additional financing.

Additionally, our projections of both the number of people who have GM1, FTD, Krabbe disease and our other product candidates, as well as the people with these diseases who have the potential to benefit from treatment with our product candidates, are based on estimates, including third party analyses commissioned by us. The total addressable market opportunity for our product candidates will ultimately depend upon, among other things, the final approved product labeling for each of our product candidates, if our product candidates are approved for sale in our target indications, acceptance by the medical community and patient access, drug pricing and reimbursement. The number of patients globally may turn out to be lower than expected, patients may not be otherwise amenable to treatment with our products, or new patients may become increasingly difficult to identify or gain access to, all of which would adversely affect our results of operations and our business. Our products may potentially be dosed on a one-time basis, which means that patients who enroll in our clinical trials may not be eligible to receive our products on a commercial basis if they are approved, leading to lower revenue potential.

Even if we complete the necessary clinical trials, we cannot predict when, or if, we will receive regulatory approval to commercialize a product candidate and the approval may be for a more narrow indication than we seek.

Prior to commercialization, our product candidates must be approved by the FDA pursuant to a biologics license application, or BLA, in the United States and by similar regulatory authorities outside the United States. The process of obtaining marketing approvals, both in the United States and abroad, is expensive and takes many years, if approval is obtained at all, and can vary substantially based upon a variety of factors, including the type, complexity and novelty of the product candidates involved. Failure to obtain marketing approval for a product candidate will prevent us from commercializing the product candidate. We have not received approval to market any of our product candidates from regulatory authorities in any jurisdiction. Our company does not have experience in submitting and supporting the applications necessary to gain marketing approvals. Securing marketing approval requires the submission of extensive preclinical and clinical data and supporting information to regulatory authorities for each therapeutic indication to establish the product candidate’s safety and efficacy. Securing marketing approval also requires the submission of information about the product manufacturing process to, and inspection of manufacturing facilities by, the regulatory authorities. Our product candidates may not be effective, may be only moderately effective or may prove to have undesirable or unintended side effects, toxicities or other characteristics that may preclude our obtaining marketing approval or prevent or limit commercial use. Regulatory authorities have substantial discretion in the approval process and may refuse to accept any application or may decide that our data are insufficient for approval and require additional preclinical, clinical or other studies. In addition, varying interpretations of the data obtained from preclinical and clinical testing could delay, limit or prevent marketing approval of a product candidate.

Approval of our product candidates may be delayed or refused for many reasons, including the following:

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Regulatory authorities also may approve a product candidate for more limited indications than requested or they may impose significant limitations in the form of narrow indications, warnings or REMS. These regulatory authorities may require precautions or contra-indications with respect to conditions of use or they may grant approval subject to the performance of costly post-marketing clinical trials. In addition, regulatory authorities may not approve the product labeling claims that are necessary or desirable for the successful commercialization of our product candidates. Any of the foregoing scenarios could materially harm the commercial prospects for our product candidates and materially and adversely affect our business, financial condition, results of operations and prospects.

The FDA and other ex-U.S. regulatory agencies have demonstrated caution in their regulation of gene therapy treatments. Ethical and legal concerns about gene therapy and genetic testing may result in additional regulations or restrictions on the development and commercialization of our product candidates, which may be difficult to predict.

The FDA and other ex-U.S. regulatory agencies at both the federal and state level in the United States, U.S. congressional committees, and foreign governments, have expressed interest in further regulating the biotechnology industry, including gene therapy and genetic testing. Any such further regulation may delay or prevent commercialization of some or all of our product candidates.

Regulatory requirements in the United States and abroad governing gene therapy products have changed frequently and may continue to change in the future. In addition to the FDA, the Institutional Biosafety Committee and IRB of each institution at which we conduct our planned clinical trials, would need to review the proposed clinical trial to assess the safety of the trial. Within the FDA, the Office of Cellular, Tissue and Gene Therapies, within the Center for Biologics Evaluation and Research, or CBER, consolidates the review of gene therapy and related products, and the Cellular, Tissue and Gene Therapies Advisory Committee advises CBER on its review. Adverse developments in clinical trials of gene therapy products conducted by others may cause the FDA or other oversight bodies to change the requirements for approval of any of our product candidates.

These regulatory review committees and advisory groups and the new guidelines they promulgate may lengthen the regulatory review process, require us to perform additional studies or trials, increase our development costs, lead to changes in regulatory positions and interpretations, delay or prevent approval and commercialization of our product

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candidates or lead to significant post-approval limitations or restrictions. As we advance our product candidates, we will be required to consult with these regulatory and advisory groups and comply with applicable guidelines. If we fail to do so, we may be required to delay or discontinue development of such product candidates. These additional processes may result in a review and approval process that is longer than we otherwise would have expected. Delays as a result of an increased or lengthier regulatory approval process or further restrictions on the development of our product candidates can be costly and could negatively impact our ability to complete clinical trials and commercialize our current and future product candidates in a timely manner, if at all.

Changes in funding for the FDA and other government agencies could hinder their ability to hire and retain key leadership and other personnel, or otherwise prevent new products and services from being developed or commercialized in a timely manner, which could negatively impact our business.

The ability of the FDA to review and approve new products can be affected by a variety of factors, including government budget and funding levels, ability to hire and retain key personnel and accept the payment of user fees, and statutory, regulatory, and policy changes. In addition, government funding of other government agencies that fund research and development activities is subject to the political process, which is inherently fluid and unpredictable.

Disruptions at the FDA and other agencies may also slow the time necessary for new drugs to be reviewed and/or approved by necessary government agencies, which would adversely affect our business. For example, over the last several years, including for 35 days beginning on December 22, 2018, the U.S. government has shut down several times and certain regulatory agencies, such as the FDA, have had to furlough critical FDA employees and stop important activities. If a prolonged government shutdown occurs, it could significantly impact the ability of the FDA to timely review and process our regulatory submissions, which could have a material adverse effect on our business.

Failure to obtain marketing approval in foreign jurisdictions would prevent our product candidates from being marketed abroad and will limit our ability to realize their full market potential.

In order to eventually market any of our product candidates in any particular foreign jurisdiction, we must establish and comply with numerous and varying regulatory requirements on a jurisdiction-by-jurisdiction basis regarding safety and efficacy. Approval by the FDA in the United States, if obtained, does not ensure approval by regulatory authorities in other countries or jurisdictions. In addition, clinical trials conducted in one country may not be accepted by regulatory authorities in other countries, and regulatory approval in one country does not guarantee regulatory approval in any other country. Approval processes vary among countries and can involve additional product testing and validation and additional administrative review periods. Seeking foreign regulatory approval could result in difficulties and costs for us and require additional preclinical studies or clinical trials which could be costly and time-consuming. Regulatory requirements can vary widely from country to country and could delay or prevent the introduction of our products in those countries. The foreign regulatory approval process involves all of the risks associated with FDA approval. In addition, gene therapy products are considered genetically-modified organism, or GMO, products and are regulated as such in each country. Designation of the type of GMO product and subsequent handling and disposal requirements can vary across countries and is variable throughout the European Union. Addressing each specific country requirement and obtaining approval to commence a clinical trial in these countries could result in delays in starting, conducting, or completing a clinical trial. We do not have any product candidates approved for sale in any jurisdiction, including international markets, and we do not have experience in obtaining regulatory approval in international markets and expect to rely on third-party consultants. If we fail to comply with regulatory requirements in international markets or to obtain and maintain required approvals, or if regulatory approvals in international markets are delayed, our target market will be reduced and our ability to realize the full market potential of our products will be unrealized.

In addition, the United Kingdom’s exit from the European Union, or the EU, which is referred to as “Brexit,” continues to create political and economic uncertainty, particularly in the United Kingdom and the EU. Since a significant proportion of the regulatory framework in the United Kingdom is derived from EU directives and regulations, the withdrawal of the United Kingdom from the EU could materially impact the regulatory regime with respect to the approval of our product candidates in the United Kingdom or the EU.

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We may not be successful in our efforts to build a pipeline of additional product candidates.

Our business model is centered on developing therapies for patients with rare, monogenic CNS disorders by establishing focused selection criteria to select, develop and advance product candidates that we believe will have a high probability of technical and regulatory success through development into commercialization. We may not be able to continue to identify and develop new product candidates in addition to the pipeline of product candidates that we have established through our collaboration with Penn’s GTP. Even if we are successful in continuing to build our pipeline, the potential product candidates that we identify may not be suitable for clinical development. For example, they may be shown to have harmful side effects or other characteristics that indicate that they are unlikely to be drugs that will receive marketing approval and achieve market acceptance. If we do not successfully develop and commercialize product candidates based upon our approach, we will not be able to obtain product revenue in future periods, which likely would result in significant harm to our financial position and adversely affect our stock price.

Risks Related to Our Reliance on Third Parties

We currently rely exclusively on our collaboration with Penn for our preclinical research and development programs, including for discovering, preclinically developing and conducting all IND-enabling studies for our lead product candidates and our near-term future pipeline. Failure or delay of Penn to fulfil all or part of its obligations to us under the agreement, a breakdown in collaboration between the parties or a complete or partial loss of this relationship would materially harm our business.

Our collaboration with Penn is critical to our business. We entered into a Research, Collaboration & License Agreement dated September 18, 2018, or the Penn Expansion Agreement, with Penn to discover and develop certain AAV vector based therapeutics, and the products developed under such collaboration currently represent all of our product pipeline and discovery programs. We recently entered into an amendment and restatement of the Penn License Agreement to expand the collaboration to include discovery research, or the Penn Expansion Agreement. We currently rely exclusively on Penn for all of our preclinical research and development capabilities, and in particular GTP under the direction of Dr. Wilson. Pursuant to the Penn Expansion Agreement, Penn is responsible for discovery, preclinical development activities, including all IND-enabling non-clinical studies and research grade manufacturing, and other collaborative activities set forth in the plan for the funded research. Either party has the right in certain circumstances to terminate the collaboration pursuant to the terms of the Penn Expansion Agreement. If Penn delays or fails to perform its obligations under the Penn Expansion Agreement, disagrees with our interpretation of the terms of the collaboration or our discovery plan or terminates our existing agreement, our pipeline of product candidates would be significantly adversely affected and our prospects will be materially harmed.

The term of the research funding portion of the Penn Expansion Agreement, under which we have the ability to acquire exclusive rights to additional gene therapy products for rare, monogenic CNS indications, expires in May 2025. In addition, the discovery program, under which we have rights to new technologies for our product candidates is currently also set to expire in May 2025. If we seek to extend our collaboration, we will need to negotiate a new or amended agreement, which may not be available to us on equally favorable terms, if at all. Penn has also entered into collaborations with third parties, including certain of our competitors, addressing targets and disease indications outside the scope of our collaboration. As a result, Penn may have competing interests with respect to their priorities and resources. We may have disagreements with Penn with respect to the interpretation of the Penn Expansion Agreement, use of resources or otherwise that could cause our relationship with Penn to deteriorate. As a result, Penn may reduce their focus on, and resources allocated to, our programs, potentially delaying or terminating our ability to advance product candidates through preclinical studies. Additionally, if Dr. Wilson were to leave Penn or to otherwise no longer be meaningfully involved with us, our preclinical research and development capabilities may be substantially reduced.

Further, under the Penn Expansion Agreement, Penn is primarily responsible for prosecuting and maintaining our licensed intellectual property, and it may fail to properly prosecute, maintain or defend such intellectual property. In such event, if we are unable to otherwise maintain or defend such intellectual property, we could face the potential invalidation of the intellectual property or be subjected to litigation or arbitration, any of which would be time-consuming and expensive. To enforce the licensed intellectual property rights under the Penn Expansion Agreement, we will need to coordinate with Penn, which could slow down or hamper our ability to enforce our licensed

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intellectual property rights. In such event, we could face increased competition that could materially and adversely affect our business.

We rely on third parties to conduct our preclinical studies, will rely on them to conduct clinical trials and rely on them to perform other tasks for us. If these third parties do not successfully carry out their contractual duties, meet expected deadlines or comply with regulatory requirements, we may not be able to obtain regulatory approval for or commercialize our product candidates and our business could be substantially harmed.

Although we have recruited a team that has experience with clinical trials, as a company we have no experience in conducting clinical trials. Moreover, we currently rely exclusively on Penn for our discovery and preclinical research and will continue to rely upon medical institutions, clinical investigators, contract laboratories and other third parties, or our CROs, to conduct future clinical trials for our product candidates. We expect to rely heavily on these parties for execution of preclinical and future clinical trials for our product candidates and control only certain aspects of their activities. If these parties reduce the levels of efforts and resources to our product candidate activities, prioritize work with a competitor of ours or if a dispute were to arise between us and these parties, they may not meet our expected deadlines or provide us with sufficient materials for our regulatory filings. Nevertheless, we will be responsible for ensuring that each of our preclinical and clinical trials is conducted in accordance with the applicable protocol, legal and regulatory requirements and scientific standards and our reliance on CROs will not relieve us of our regulatory responsibilities. 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.

We, Penn and our CROs will be required to comply with regulations, including cGCPs for conducting, monitoring, recording and reporting the results of preclinical and clinical trials to ensure that the data and results are scientifically credible and accurate and that the trial patients are adequately informed of the potential risks of participating in clinical trials and their rights are protected. These regulations are enforced by the FDA, the Competent Authorities of the Member States of the European Economic Area and comparable foreign regulatory authorities for any drugs in clinical development. The FDA enforces cGCP regulations through periodic inspections of clinical trial sponsors, principal investigators and trial sites. If we or our CROs fail to comply with applicable cGCPs, the clinical data generated in our clinical trials may be deemed unreliable and the FDA or comparable foreign regulatory authorities may require us to perform additional clinical trials before approving our marketing applications. We cannot assure you that, upon inspection, the FDA will determine that any of our future clinical trials will comply with cGCPs. In addition, our clinical trials must be conducted with product candidates produced in accordance with the requirements in cGMP regulations. Our failure or the failure of our CROs to comply with these regulations may require us to repeat clinical trials, which would delay the regulatory approval process and could also subject us to enforcement action.

Although we currently design and intend to continue designing our planned clinical trials for our product candidates, for the foreseeable future CROs will conduct all of our planned clinical trials. As a result, many important aspects of our development programs, including their conduct and timing, will be outside of our direct control. Our reliance on third parties to conduct future preclinical studies and clinical trials will also result in less day-to-day control over the management of data developed through preclinical studies and clinical trials than would be the case if we were relying entirely upon our own staff.

If any of our relationships with these third-party CROs terminate, we may not be able to enter into arrangements with alternative CROs. If CROs do not successfully carry out their contractual duties or obligations or meet expected deadlines, if they need to be replaced or if the quality or accuracy of the clinical data they obtain is compromised due to the failure to adhere to our clinical protocols, regulatory requirements or for other reasons, any preclinical studies or clinical trials with which such CROs are associated with may be extended, delayed or terminated. In such cases, we may not be able to obtain regulatory approval for or successfully commercialize our product candidates. As a result, our financial results and the commercial prospects for our product candidates in the subject indication could be harmed, our costs could increase and our ability to generate revenue could be delayed.

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We expect to rely on third parties to conduct our clinical trials. If those third parties do not perform as contractually required, fail to satisfy legal or regulatory requirements, miss expected deadlines or terminate the relationship, our development program could be delayed with potentially material and adverse effects on our business, financial condition, results of operations and prospects.

We expect to rely on third-party clinical investigators, CROs, clinical data management organizations and consultants to assist or provide the design, conduct, supervision and monitoring of clinical trials of our product candidates. Because we intend to rely on these third parties and will not have the ability to conduct all clinical trials independently, we will have less control over the timing, quality and other aspects of clinical trials than we would have had we conducted them on our own. These investigators, CROs and consultants will not be our employees and we will have limited control over the amount of time and resources that they dedicate to our programs. These third parties may have contractual relationships with other entities, some of which may be our competitors, which may draw time and resources from our programs. The third parties with which we may contract might not be diligent, careful or timely in conducting our clinical trials, resulting in the clinical trials being delayed or unsuccessful.

If we cannot contract with acceptable third parties on commercially reasonable terms, or at all, or if these third parties do not carry out their contractual duties, satisfy legal and regulatory requirements for the conduct of preclinical studies or clinical trials or meet expected deadlines, our clinical development programs could be delayed and otherwise adversely affected. In all events, we will be responsible for ensuring that each of our preclinical studies and clinical trials are conducted in accordance with the general investigational plan and protocols for the trial as well as applicable legal and regulatory requirements. The FDA generally requires preclinical studies to be conducted in accordance with good laboratory practices and clinical trials to be conducted in accordance with good clinical practices, including for designing, conducting, recording and reporting the results of preclinical studies and clinical trials to assure that data and reported results are credible and accurate and that the rights, integrity and confidentiality of clinical trial participants are protected. Our reliance on third parties that we do not control will not relieve us of these responsibilities and requirements. Any adverse development or delay in our preclinical studies or clinical trials as a result of our reliance on third parties could have a material and adverse effect on our business, financial condition, results of operations and prospects.

If any of our relationships with these third-party CROs or others terminate, we may not be able to enter into alternative arrangements or to do so on commercially reasonable terms. Switching or adding additional CROs involves additional cost and requires management time and focus. In addition, there is a natural transition period when a new CRO begins work. As a result, delays may occur, which can materially adversely impact our ability to meet our desired clinical development timelines.

We may in the future enter into collaborations with other third parties for the discovery, development and commercialization of our product candidates. If any of our current or future collaborators cease development efforts under our collaboration agreements, or if any of those agreements are terminated, these collaborations may fail to lead to commercial products and we may never receive milestone payments or future royalties under these agreements.

We may in the future enter into third-party collaborations for research, development and commercialization of other therapeutic technologies or product candidates. Biotechnology companies are our likely future collaborators for any marketing, distribution, development, licensing or broader collaboration arrangements.

With any future collaboration agreements, we expect to have limited control over the amount and timing of resources that our collaborators dedicate to the development or commercialization of our product candidates. Moreover, 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.

Our potential future collaborations involving our product candidates may pose the following risks to us:

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As a result of the foregoing, any future collaboration agreements may not lead to development or commercialization of our product candidates in the most efficient manner or at all. If a collaborator of ours were to be involved in a business combination, the continued pursuit and emphasis on our product development or commercialization program could be delayed, diminished or terminated. Any failure to successfully develop or commercialize our product candidates pursuant to our current or any future collaboration agreements could have a material and adverse effect on our business, financial condition, results of operations and prospects.

Moreover, to the extent that any of our existing or future collaborators were to terminate a collaboration agreement, we may be forced to independently develop our product candidates and discovery programs, including funding preclinical studies or clinical trials, assuming marketing and distribution costs and maintaining and defending intellectual property rights, or, in certain instances, abandon product candidates altogether, any of which could result in a change to our business plan and have a material adverse effect on our business, financial condition, results of operations and prospects.

We may not be successful in finding additional collaborators for continuing development of certain of our product candidates or successfully commercializing or competing in the market for certain indications.

We may decide to pursue collaborations with additional pharmaceutical and biotechnology companies for the development and potential commercialization of some of our product candidates. We face significant competition in seeking appropriate collaborators. Any new collaboration may be on terms that are not optimal for us, and we may not be able to maintain any new collaboration if, for example, development or approval of a product candidate is delayed,

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sales of an approved product candidate do not meet expectations or the collaborator terminates the collaboration. In addition, a significant number of recent business combinations among large pharmaceutical companies has 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 the design or results of clinical trials, the likelihood of approval by 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 drugs, the existence of uncertainty with respect to our ownership of technology, which can exist if there is a challenge to such ownership without regard to the merits of the challenge and industry and market conditions generally. The collaborator may also consider alternative product candidates or technologies for similar indications that may be available to collaborate on and whether such a collaboration could be more attractive than the one with us for our product candidate. The terms of any additional collaborations or other arrangements that we may establish may not be favorable to us.

We may also be restricted under existing collaboration agreements from entering into future agreements on certain terms with potential collaborators. Collaborations are complex and time-consuming to negotiate and document. 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.

We may not be able to negotiate additional collaborations on a timely basis, on acceptable terms, or at all. If we are unable to do so, we may have to curtail the development of the product candidate for which we are seeking to collaborate, reduce or delay its development program or one or more of our other development programs, delay its potential commercialization or reduce the scope of any sales or marketing activities, or increase our expenditures and undertake development or commercialization activities at our own expense. If we elect to increase our expenditures to fund development or commercialization activities on our own, we may need to obtain additional capital, which may not be available to us on acceptable terms or at all. If we do not have sufficient funds, we may not be able to further develop our product candidates or bring them to market and generate product revenue.

We may have conflicts with our collaborators that could delay or prevent the development or commercialization of our product candidates.

We may have conflicts with our collaborators, including Penn, such as conflicts concerning the interpretation of preclinical or clinical data, the achievement of milestones, the interpretation of contractual obligations, payments for services, development obligations or the ownership of intellectual property developed during our collaboration. If any conflicts arise with any of our collaborators, including Penn, such collaborator may act in a manner that is adverse to our best interests. Any such disagreement could result in one or more of the following, each of which could delay or prevent the development or commercialization of our product candidates, and in turn prevent us from generating revenues: unwillingness on the part of a collaborator to pay us milestone payments or royalties we believe are due to us under a collaboration, which could require us to raise additional capital; uncertainty regarding ownership of intellectual property rights arising from our collaborative activities, which could prevent us from entering into additional collaborations; unwillingness by the collaborator to cooperate in the development or manufacture of the product, including providing us with product data or materials; unwillingness on the part of a collaborator to keep us informed regarding the progress of its development and commercialization activities or to permit public disclosure of the results of those activities; initiating of litigation or alternative dispute resolution options by either party to resolve the dispute; or attempts by either

We may in the future seek to engage in strategic transactions to acquire or in-license new products, product candidates or technologies. If we are unable to successfully complete, or realize the benefits from, such transactions it may adversely affect our ability to develop and commercialize product candidates, impact our cash position, increase our expenses and present significant distractions to our management.

From time to time, we may consider strategic transactions, such as additional collaborations, acquisitions of companies, asset purchases, joint ventures and in-licensing of new products, product candidates or technologies that we believe will complement or augment our existing business. If we acquire assets with promising markets or technologies, we may not be able to realize the benefit of acquiring such assets if we are not able to successfully integrate them with our existing

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technologies. We may encounter numerous difficulties in developing, testing, manufacturing and marketing any new products resulting from a strategic acquisition that delay or prevent us from realizing their expected benefits or enhancing our business.

We cannot assure you that following any such strategic transaction, we will achieve the expected synergies to justify the transaction. For example, such transactions may require us to incur non-recurring or other charges, increase our near- and long-term expenditures and pose significant integration or implementation challenges or disrupt our management or business. These transactions would entail numerous operational and financial risks, including exposure to unknown liabilities, disruption of our business and diversion of our management’s time and attention in order to manage a collaboration or develop acquired products, product candidates or technologies, incurrence of substantial debt or dilutive issuances of equity securities to pay transaction consideration or costs, higher than expected acquisition or integration costs, write-downs of assets or goodwill or impairment charges, increased amortization expenses, difficulty and cost in facilitating the transaction or combining the operations and personnel of any acquired business, impairment of relationships with key suppliers, manufacturers or customers of any acquired business due to changes in management and ownership and the inability to retain key employees of any acquired business.

Accordingly, although there can be no assurance that we will undertake or successfully complete any transactions of the nature described above, any transactions that we do complete may be subject to the foregoing or other risks and would have a material and adverse effect on our business, financial condition, results of operations and prospects. Conversely, any failure to enter any strategic transaction that would be beneficial to us could delay the development and potential commercialization of our product candidates and have a negative impact on the competitiveness of any product candidate that reaches market.

Risks Related to Manufacturing

Gene therapies are novel, complex and difficult to manufacture. We could experience manufacturing problems that result in delays in our development or commercialization programs or otherwise harm our business.

We currently rely on third parties to develop, manufacture and test clinical supplies of our product candidates. For our initial clinical trials, we will rely on the manufacturing facility of Catalent Maryland (formerly Paragon Bioscience), or Catalent, for supply of our product candidates, and on Penn to manage the transfer of technology to Catalent that is necessary for production. We expect to establish our own manufacturing facility for long-term commercial market supply. However, we have limited experience as a company in developing manufacturing facilities. We may face delays in constructing our facilities and transferring technology to our facilities or have difficulty hiring experts to staff and operate our own manufacturing facility and, accordingly, our production capacity could be limited. The manufacturing processes used to produce our product candidates are complex, novel and have not been validated for commercial use. Many factors could cause production interruptions, including equipment malfunctions, facility contamination, raw material shortages or contamination, natural disasters, disruption in utility services, human error or disruptions in the operations of our suppliers.

Our product candidates require processing steps that are more complex than those required for most small molecule drugs. Moreover, unlike small molecules, the physical and chemical properties of a biologic such as ours generally cannot be fully characterized. As a result, assays of the finished product may not be sufficient to ensure that the product is consistent from lot-to-lot or will perform in the intended manner. Accordingly, we employ multiple steps to control the manufacturing process to assure that the process works consistently and the product candidate is made strictly and consistently in compliance with the process. Problems with the manufacturing process, even minor deviations from the normal process, could result in product defects or manufacturing failures that result in lot failures, low lot yields, product recalls, product liability claims or insufficient inventory. As a result, we may encounter problems achieving adequate quantities and quality of clinical-grade materials that meet the FDA or other applicable standards or specifications with consistent and acceptable production yields and costs.

In addition, the FDA and ex-U.S. regulatory authorities may require us to submit samples of any lot of any approved product together with the protocols showing the results of applicable tests at any time. Under some circumstances, the FDA or ex-U.S. regulatory authorities may require that we not distribute a lot until the agency authorizes its release.

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Slight deviations in the manufacturing process, including those affecting quality attributes and stability, may result in unacceptable changes in the product that could result in lot failures, low lot yields or product recalls. Lot failures, low lot yields or product recalls could cause us to delay product launches or clinical trials, which could be costly to us and otherwise harm our business, financial condition, results of operations and prospects.

We, or our third-party collaborators, also may encounter problems hiring and retaining the experienced scientific, quality-control and manufacturing personnel needed to operate our manufacturing processes, which could result in delays in production or difficulties in maintaining compliance with applicable regulatory requirements.

Any problems in our, or our third-party collaborators’, manufacturing process or facilities could result in delays in our planned clinical trials and increased costs, and could make us a less attractive collaborator for potential partners, including larger biotechnology companies and academic research institutions, which could limit our access to additional attractive development programs. It could also require us to find alternative manufacturing processes, which may be unavailable to us on attractive terms, or at all. Problems in our manufacturing process could restrict our ability to meet potential future market demand for our products.

Changes in methods of product candidate manufacturing or formulation may result in additional costs or delay.

As product candidates proceed through preclinical studies to late-stage clinical trials towards potential approval and commercialization, it is common that various aspects of the development program, such as manufacturing methods and formulation, are altered along the way in an effort to optimize processes and results. Such changes carry the risk that they will not achieve these intended objectives. Any of these changes could cause our product candidates to perform differently and affect the results of planned clinical trials or other future clinical trials conducted with the materials manufactured using altered processes. Such changes may also require additional testing, FDA notification or FDA approval. This could delay completion of clinical trials, require the conduct of bridging clinical trials or the repetition of one or more clinical trials, increase clinical trial costs, delay approval of our product candidates and jeopardize our ability to commence sales and generate revenue.

We currently rely and expect to continue to rely on third-party manufacturers to produce clinical supply of our product candidates, and we have not entered into binding agreements with any such manufacturers to support commercialization. The competition for gene therapy contract development, manufacturing and testing services is intense. Additionally, these manufacturers do not have experience producing our product candidates at commercial levels and may not achieve the necessary regulatory approvals or produce our product candidates at the quality, quantities, locations and timing needed to support commercialization.

We do not currently plan to independently manufacture most of the material for our planned clinical programs. We currently rely, and expect to continue to rely, on third parties for the production of our preclinical study and planned clinical trial materials and, therefore, we can control only certain aspects of their activities. The competition for gene therapy contract development, manufacturing and testing is intense. Reliance on third-party manufacturers may expose us to different risks than if we were to manufacture product candidates ourselves, including but not limited to potential competition from other genetic biotechnology companies for the use of such third-party manufacturers.

While we have secured an agreement with Catalent to manufacture clinical supply of our product candidates, we have not yet secured manufacturing capabilities for commercial quantities of our product candidates. Although we intend to establish our own manufacturing facility for long-term commercial market supply, we may need to rely on third-party manufacturers for commercialization of our product candidates if regulatory approval is achieved. To date, while we have a collaboration agreement with Catalent for a dedicated clean room suite, we have only entered into agreements with such manufacturer to support our clinical studies. We may be unable to negotiate binding agreements with the manufacturers to support our potential commercialization activities at commercially reasonable terms.

Before any of our third-party manufacturers and suppliers can begin to commercially manufacture our product candidates, they must demonstrate to regulatory authorities that the planned chemistry, manufacturing and controls for our gene therapy product candidates meet certain requirements. Manufacturing of product candidates for clinical and commercial purposes must comply with the cGMP and applicable ex-U.S. regulatory requirements. The cGMP

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requirements govern quality control and documentation policies and procedures. Complying with cGMP and ex-U.S. regulatory requirements will require that we expend time, money and effort in production, recordkeeping and quality control to assure that our product candidates meet applicable specifications and other requirements. Our third-party manufacturers’ also must demonstrate to the FDA that they can make the product candidate in accordance with the cGMP requirements as part of a pre-approval inspection prior to FDA approval of the product candidate. Failure to pass a pre-approval inspection might significantly delay FDA approval of our product candidates. If any of our third-party manufacturers fail to comply with these requirements, we would be subject to possible regulatory action, which could limit the jurisdictions in which we are permitted to sell our products. As a result, our business, financial condition and results of operations may be materially harmed.

In addition, our third-party manufacturers may fail to comply with cGMP regulations or similar regulatory requirements outside the United States. Our failure, or the failure of our third-party manufacturers, to comply with applicable regulations could result in sanctions being imposed on us, including clinical holds, fines, injunctions, civil penalties, delays, suspension or withdrawal of approvals, license revocation, seizures or recalls of product candidates or products, operating restrictions and criminal prosecutions, any of which could significantly and adversely affect supplies of our product candidates.

Even if our third-party manufacturers comply with applicable regulatory requirements, we cannot assure you that they will be able to successfully manufacture additional product candidates at a larger scale in a timely or economical manner, or at all. If they are unable to successfully increase our manufacturing scale or capacity, the development, testing, and clinical trials of our product candidates may be delayed or infeasible, and regulatory approval or commercial launch of any resulting product may be delayed or not obtained, which could significantly harm our business.

Our third-party manufacturers and suppliers use biological materials and may use hazardous materials, and any claims relating to improper handling, storage or disposal of these materials could be time consuming or costly.

Our third-party manufacturers and suppliers may use hazardous materials, including chemicals and biological agents and compounds that could be dangerous to human health and safety or the environment. The operations of our third-party manufacturers and suppliers also produce hazardous waste products. Federal, state and local laws and regulations govern the use, generation, manufacture, storage, handling and disposal of these materials and wastes. Compliance with applicable environmental laws and regulations may be expensive, and current or future environmental laws and regulations may impair our product development efforts. In addition, we cannot entirely eliminate the risk of accidental injury or contamination from these materials or wastes. 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 our clinical trials or regulatory approvals could be suspended.

Any contamination in our third parties’ manufacturing process, shortages of raw materials, labor or reagents or failure of any of our key suppliers to deliver necessary components of our platform could result in delays in our clinical development or marketing schedules.

Given the nature of biologics manufacturing, there is a risk of contamination. Any contamination could materially adversely affect our or our third-party vendor’s ability to produce our gene therapies on schedule and could therefore harm our results of operations and cause reputational damage.

The raw materials required in our third-party vendors manufacturing processes are derived from biological sources. We cannot assure you that our third-party vendors have, or will be able to obtain on commercially reasonable terms, or at all, sufficient rights to these materials derived from biological sources. Such raw materials are difficult to procure and may also be subject to contamination or recall. A material shortage, contamination, recall, or restriction on the use of biologically derived substances in the manufacture of our product candidates could adversely impact or disrupt the clinical and commercial manufacturing of our product candidates, which could materially and adversely affect our operating results and development timelines.

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We rely on third-party suppliers for the supply and manufacture of certain components of our technology. Should our ability to procure these material components from our suppliers be compromised, our ability to continuously operate would be impaired until an alternative supplier is sourced, qualified and tested, which could limit our ability to produce a clinical and commercial supply of our product candidates and harm our business.

We depend on third-party suppliers for materials used in the manufacture of our product candidates, and the loss of these third-party suppliers or their inability to supply us with adequate materials could harm our business.

We rely on third-party suppliers for certain materials and components required for the production of our product candidates. Our dependence on these third-party suppliers and the challenges we may face in obtaining adequate supplies of materials involve several risks, including limited control over pricing, availability, and quality and delivery schedules. There is substantial demand and limited supply for certain of the raw materials used to manufacture gene therapy products. As a small company, our negotiation leverage is limited and we are likely to get lower priority than our competitors that are larger than we are. We cannot be certain that our suppliers will continue to provide us with the quantities of these raw materials that we require or satisfy our anticipated specifications and quality requirements. Any supply interruption in limited or sole sourced raw materials could materially harm our ability to manufacture our product candidates until a new source of supply, if any, could be identified and qualified. We may be unable to find a sufficient alternative supply channel in a reasonable time or on commercially reasonable terms. Any performance failure on the part of our suppliers could delay the development and potential commercialization of our product candidates, including limiting supplies necessary for clinical trials and regulatory approvals, which would have a material adverse effect on our business.

Risks Related to Commercialization

We face significant competition in an environment of rapid technological change and the possibility that our competitors may achieve regulatory approval before us or develop therapies or technologies that are more advanced or effective than ours, which may harm our business and financial condition, and our ability to successfully market or commercialize our product candidates.

The biotechnology and pharmaceutical industries, including the genetic medicines field, are characterized by rapidly changing technologies, competition and a strong emphasis on intellectual property. We are aware of several companies focused on developing gene therapies in various indications as well as several companies addressing methods for modifying genes and regulating gene expression. We may also face competition from large and specialty pharmaceutical and biotechnology companies, academic research institutions, government agencies and public and private research institutions.

For the treatment of GM1, there are no approved disease-modifying therapies. We consider our most direct competitors with respect to PBGM01 for the treatment of GM1 to be Axovant Gene Therapies, Ltd., which began its clinical trial for a gene therapy treatment for juvenile GM1 in May 2019, and Lysogene, S.A., which is expected to submit an IND in the first half of 2020 for a gene therapy treatment for GM1.

For the treatment of FTD, there are no approved disease-modifying therapies. We consider our most direct competitors with respect to PBFT02 for the treatment of FTD-GRN to be Alector, Inc., which is conducting a Phase 2 clinical trial immune-neurology treatment for FTD-GRN and Prevail Therapeutics Inc., which is expected to initiate soon a clinical trial for a gene therapy treatment for FTD-GRN. Alkermes plc and Arkuda Therapeutics, Inc. are conducting preclinical research into small molecule approaches targeting specific histone deacetylase treat FTD-GRN patients. We are also aware of other therapeutic approaches in preclinical development that may target FTD-GRN patients.

For the treatment of Krabbe disease, there are no approved disease-modifying therapies. We are not aware of any companies with clinical stage gene therapy product candidates for the treatment of Krabbe disease. We are aware of an ongoing disease progression study being conducted by the Children’s Hospital of Pittsburgh and certain academic studies. There is some evidence that human stem cell transplant is beneficial for pre-symptomatic infants with Krabbe disease.

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Many of our potential competitors, alone or with their strategic partners, have substantially greater financial, technical, and other resources than we do, such as larger research and development, clinical, marketing and manufacturing organizations. Mergers and acquisitions in the biotechnology and pharmaceutical industries may result in even more resources being concentrated among a smaller number of competitors. Our commercial opportunity could be reduced or eliminated if competitors develop and commercialize products that are safer, more effective, have fewer or less severe side effects, are more convenient or are less expensive than any product candidates that we may develop. Competitors also may obtain FDA or other regulatory approval for their products more rapidly than we may obtain approval for ours, which could result in our competitors establishing a strong market position before we are able to enter the market, if ever. Additionally, new or advanced technologies developed by our competitors may render our current or future product candidates uneconomical or obsolete, and we may not be successful in marketing our product candidates against competitors.

The commercial success of any of our product candidates will depend upon its degree of market acceptance by physicians, patients, third-party payors and others in the medical community.

Ethical, social and legal concerns about gene therapy could result in additional regulations restricting or prohibiting our products. Even with the requisite approvals from the FDA in the United States and other regulatory authorities internationally, the commercial success of our product candidates will depend, in part, on the acceptance of physicians, patients and health care payors of gene therapy products in general, and our product candidates in particular, as medically necessary, cost-effective and safe. Any product that we commercialize may not gain acceptance by physicians, patients, health care payors and others in the medical community. If these products do not achieve an adequate level of acceptance, we may not generate significant product revenue and may not become profitable. The degree of market acceptance of gene therapy products and, in particular, our product candidates, if approved for commercial sale, will depend on several factors, including:

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Even if a potential product displays a favorable efficacy and safety profile in preclinical studies and clinical trials, market acceptance of the product will not be fully known until after it is launched.

If in the future we are unable to establish U.S. or global sales and marketing capabilities or enter into agreements with third parties to sell and market our product candidates, we may not be successful in commercializing our product candidates if they are approved and we may not be able to generate any revenue.

We currently do not have a marketing or sales team for the marketing, sales and distribution of any of our product candidates that may receive regulatory approval. In order to commercialize any product candidates after approval, we must build on a territory-by-territory basis marketing, sales, distribution, managerial and other non-technical capabilities or make arrangements with third parties to perform these services, and we may not be successful in doing so. If our product candidates receive regulatory approval, we may decide to establish an internal sales or marketing team with technical expertise and supporting distribution capabilities to commercialize our product candidates, which will be expensive and time-consuming and will require significant attention of our executive officers to manage. Any failure or delay in the development of our internal sales, marketing and distribution capabilities would adversely impact the commercialization of any of our product candidates that we obtain approval to market.

With respect to the commercialization of all or certain of our product candidates, we may choose to collaborate, either globally or on a territory-by-territory basis, with third parties that have direct sales forces and established distribution systems, either to augment our own sales force and distribution systems or in lieu of our own sales force and distribution systems. If we are unable to enter into such arrangements when needed on acceptable terms, or at all, we may not be able to successfully commercialize any of our product candidates that receive regulatory approval or any such commercialization may experience delays or limitations. If we are not successful in commercializing our product candidates, either on our own or through collaborations with one or more third parties, our future product revenue will suffer and we may incur significant additional losses.

We may expend our limited resources to pursue a particular product candidate or indication and fail to capitalize on product candidates or indications that may be more profitable or for which there is a greater likelihood of success.