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 6, 2021

Aileron Therapeutics, Inc.

(Exact Name of Company as Specified in Charter)

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

Not applicable

(Former Name or Former Address, if Changed Since Last Report)

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 (see General Instruction A.2. below):

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 6, 2021, Aileron Therapeutics, Inc. (the “Company”) entered into a securities purchase agreement (the “Purchase Agreement”) with certain institutional investors (the “Purchasers”), pursuant to which the Company agreed to issue and sell, in a registered direct offering (the “Offering”), an aggregate of 32,630,983 shares of common stock, $0.001 par value per share, of the Company (the “Common Stock”), at a purchase price per share of $1.10 (the “Shares”). The aggregate gross proceeds to the Company in the Offering are expected to be $35.9 million, before deducting fees payable to the placement agent and other estimated offering expenses payable by the Company The Shares are being offered by the Company pursuant to a shelf registration statement on Form S-3 (File No. 333-226650) that was filed with the United States Securities and Exchange Commission (“SEC”) on July 1, 2018, and declared effective by the SEC on July 15, 2019, and a prospectus supplement thereunder. The Offering is expected to close on or about January 8, 2021, subject to customary closing conditions.

Pursuant to the Placement Agent Agreement between the Company and JonesTrading Institutional Services LLC (“JonesTrading”), dated as of January 6, 2021, the Company will pay placement agent fees of approximately $2.2 million to JonesTrading and will reimburse JonesTrading for its reasonable and documented out-of-pocket expenses incurred in connection with the Offering, including its legal expenses, subject to a limit of $35,000 in the case of its legal expenses.

The Purchase Agreement contains customary representations, warranties, covenants and agreements by the Company, customary conditions to closing, indemnification obligations, other obligations of the parties and termination provisions. The representations, warranties and covenants contained in the Purchase Agreement were made only for purposes of such agreement and as of specific dates, were solely for the benefit of the parties to such agreement, and may be subject to limitations agreed upon by the contracting parties. The foregoing description of the Purchase Agreement is qualified in its entirety by reference to the full text of the Purchase Agreement, a copy of which is filed herewith as Exhibit 10.1 to this Current Report on Form 8-K and is incorporated by reference herein.

A copy of the legal opinion and consent of Wilmer Cutler Pickering Hale and Dorr LLP, counsel to the Company, relating to the Shares is attached as Exhibit 5.1 to this Current Report on Form 8-K.

On January 6, 2021, the Company issued a press release announcing the pricing of the Offering. A copy of the press release has been filed as Exhibit 99.1 hereto and is incorporated herein by reference.

(d) Exhibits:

SIGNATURES

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