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): July 12, 2019

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 July 12, 2019, Aileron Therapeutics, Inc. (the “Company”) received a deficiency letter from the Listing Qualifications Department (the “Staff”) of the Nasdaq Stock Market (“Nasdaq”) notifying the Company that, for the last 30 consecutive business days, the bid price for the Company’s common stock had closed below the minimum $1.00 per share requirement for continued inclusion on the Nasdaq Global Market pursuant to Nasdaq Listing Rule 5450(a)(1) (the “Bid Price Rule”). The deficiency letter does not result in the immediate delisting of the Company’s common stock from the Nasdaq Global Market. In accordance with Nasdaq Listing Rule 5810(c)(3)(A) (the “Compliance Period Rule”), the Company has been provided an initial period of 180 calendar days, or until January 8, 2020 (the “Compliance Date”), to regain compliance with the Bid Price Rule. If, at any time before the Compliance Date, the bid price for the Company’s common stock closes at $1.00 or more per share for a minimum of 10 consecutive business days, as required under the Compliance Period Rule, the Staff will provide written notification to the Company that it complies with the Bid Price Rule, unless the Staff exercises its discretion to extend this 10-day period pursuant to Nasdaq Listing Rule 5810(c)(3)(G).

If the Company does not regain compliance with the Bid Price Rule by the Compliance Date, the Company may be eligible for an additional 180 calendar day compliance period. To qualify, the Company would need to transfer the listing of its common stock to the Nasdaq Capital Market, provided that it meets the continued listing requirement for the market value of publicly held shares and all other initial listing standards, with the exception of the Bid Price Rule. To effect such a transfer, the Company would also need to pay an application fee to Nasdaq and will need to provide written notice to the Staff of its intention to cure the deficiency during the additional compliance period.

If the Company does not regain compliance with the Bid Price Rule by the Compliance Date and is not eligible for an additional compliance period at that time, the Staff will provide written notification to the Company that its common stock may be delisted. At that time, the Company may appeal the Staff’s delisting determination to a Nasdaq Listing Qualifications Panel (the “Panel”). The Company expects that its stock would remain listed pending the Panel’s decision. There can be no assurance that, if the Company does appeal the Staff’s delisting determination to the Panel, such appeal would be successful.

The Company intends to monitor the closing bid price of its common stock and may, if appropriate, consider available options to regain compliance with the Bid Price Rule, which could include seeking to effect a reverse stock split. However, there can be no assurance that the Company will be able to regain compliance with the Bid Price Rule.

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.