Company: KROS
Filing Date: 2025-05-19
Form Type: DEFA14A
Source: 0001104659-25-050245
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Company: Keros Therapeutics, Inc.
Filing Date: 2025-05-19
Form: DEFA14A
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<div align='center'>UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

PROXY STATEMENT PURSUANT TO SECTION 14(a) OF THE

SECURITIES EXCHANGE ACT OF 1934</div>

Filed by the Registrant x

Filed by a Party other than the Registrant ¨

Check the appropriate box:

| ¨ |     | Preliminary Proxy Statement                                                     |
| ¨ |     | Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) |
| ¨ |     | Definitive Proxy Statement                                                      |
| x |     | Definitive Additional Materials                                                 |
| ¨ |     | Soliciting Material Pursuant to §240.14a-12                                     |

<div align='center'>Keros Therapeutics, Inc.

(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement if other than the Registrant)</div>

Payment of Filing Fee (Check the appropriate box):

| x |     | No fee required.                                                                                    |
| ¨ |     | Fee paid previously with preliminary materials.                                                     |
| ¨ |     | Fee computed on table in exhibit required by Item 25(b) per Exchange Act Rule 14a-6(i)(1) and 0-11. |

This Schedule 14A filing consists of the following press release issued by Keros Therapeutics, Inc. (the “Company”), relating to a presentation and open letter distributed by the Company to its stockholders in connection with the Company’s 2025 Annual Meeting of Stockholders. The press release was first used or made available on May 19, 2025.

<div align='center'>Keros Therapeutics Highlights Commitment to Maximizing Stockholder Value

Files Investor Presentation and Issues Open Letter to Stockholders

Urges Stockholders to Protect the Value of Their Investment by Voting “FOR”Each of the Company’s Highly Qualified Director Nominees</div>

Lexington, Mass., May 19, 2025 –Keros Therapeutics, Inc. (“Keros”, the “Company” or “we”) (Nasdaq:
KROS), a clinical-stage biopharmaceutical company focused on developing and commercializing novel therapeutics to treat a wide range of
patients with disorders that are linked to dysfunctional signaling of the transforming growth factor-beta (“TGF-ß”)
family