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): April 13, 2020

Keros Therapeutics, Inc.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (617) 314-6297

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.  ☐

Amendment and Restatement of Certificate of Incorporation

On April 13, 2020, Keros Therapeutics, Inc. (the “Company”) filed an amended and restated certificate of incorporation (the “Restated Certificate”) with the Secretary of State of the State of Delaware, in connection with the closing of the Company’s initial public offering of shares of its common stock. The Company’s board of directors and stockholders previously approved the Restated Certificate to be filed in connection with, and to be effective upon, the closing of the Company’s initial public offering. A description of certain provisions of the Restated Certificate is set forth in the section titled “Description of Capital Stock” in the final prospectus the Company filed with the U.S. Securities and Exchange Commission on April 8, 2020 pursuant to Rule 424(b) under the Securities Act of 1933, as amended, relating to the Registration Statement on Form S-1, as amended (File No. 333-237212) (the “Prospectus”).

Amendment and Restatement of Bylaws

Effective as of April 13, 2020, the Company adopted amended and restated bylaws (the “Restated Bylaws”) in connection with the closing of the Company’s initial public offering. The Company’s board of directors and stockholders previously approved the Restated Bylaws to become effective upon the closing of the Company’s initial public offering. A description of certain provisions of the Restated Bylaws is set forth in the section of the Prospectus titled “Description of Capital Stock.”

The foregoing descriptions of the Restated Certificate and the Restated Bylaws are qualified in their entirety by reference to the full texts of the Restated Certificate and the Restated Bylaws, which are filed as Exhibits 3.1 and 3.2 hereto and are incorporated by reference herein.

On April 13, 2020, the Company closed its initial public offering of 6,900,000 shares of its common stock, par value $0.0001 per share, which includes the exercise in full by the underwriters of their option to purchase up to 900,000 additional shares, at a price to the public of $16.00 per share. The gross proceeds to the Company from the initial public offering were $110.4 million, before deducting underwriting discounts and commissions and offering expenses payable by the Company.

(d) Exhibits.

SIGNATURES

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.

Dated: April 13, 2020