UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(d)

OF THE SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of earliest event reported): January 29, 2021

Aileron Therapeutics, Inc.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (617) 995-0900

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

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

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company  ☒

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.  ☒

On January 29, 2021, Aileron Therapeutics, Inc., a Delaware corporation (the “Company”), entered into a Capital on Demand^™ Sales Agreement (the “Sales Agreement”) with JonesTrading Institutional Services LLC and William Blair & Company, L.L.C. (each, an “Agent” and collectively, the “Agents”), pursuant to which the Company may offer and sell shares of its common stock, $0.001 par value per share, having an aggregate offering price of up to $30,000,000 (the “Shares”) from time to time through or to the Agents (the “Offering”). On January 29, 2021, the Company filed a prospectus supplement with the Securities and Exchange Commission in connection with the Offering (the “Prospectus Supplement”) under its existing Registration Statement on Form S-3 (File No. 333-226650), which became effective on August 7, 2018 (the “Registration Statement”).

Upon delivery of a placement notice and subject to the terms and conditions of the Sales Agreement, the Agents may sell the Shares in accordance with the terms set forth in the placement notice and by methods deemed to be “at the market offerings” as defined in Rule 415(a)(4) promulgated under the Securities Act of 1933, as amended (the “Securities Act”).

The Company or the Agents may suspend or terminate the offering of Shares upon notice to the other party and subject to certain conditions. An Agent will act as sales agent using commercially reasonable efforts consistent with its normal trading and sales practices and applicable state and federal law, rules and regulations and the rules of the Nasdaq Stock Market LLC.

The Company has agreed to pay the Agents commissions for their services in acting as agents in the sale of the Shares in the amount of up to 3.0% of gross sales price per share sold under the Sales Agreement. The Company has also agreed to provide the Agents with indemnification and contribution with respect to certain liabilities, including civil liabilities under the Securities Act.

A copy of the Sales Agreement is attached as Exhibit 1.1 hereto and is incorporated herein by reference. The foregoing description of the material terms of the Sales Agreement does not purport to be complete and is qualified in its entirety by reference to such exhibit.

Wilmer Cutler Pickering Hale and Dorr LLP, counsel to the Company, has issued a legal opinion relating to the Shares. A copy of such legal opinion, including the consent included therein, is attached as Exhibit 5.1 hereto.

The Shares will be sold pursuant to the Registration Statement and offerings of the Shares will be made only by means of the Prospectus Supplement. This Current Report on Form 8-K shall not constitute an offer to sell or solicitation of an offer to buy these securities, nor shall there be any sale of these securities in any state in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities law of such state or jurisdiction.

(d) Exhibits

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.