Company: KROS
Filing Date: 2025-05-09
Form Type: DEFA14A
Source: 0001104659-25-046272
Chunk: 0

Company: Keros Therapeutics, Inc.
Filing Date: 2025-05-09
Form: DEFA14A
Chunk 0
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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 stockholder’s announcement on withholding votes from two director nominees, Mary Ann Gray, Ph.D., and Alpna Seth, Ph.D., both of whom are current members of the Company’s
Board of Directors and standing for re-election at the Company’s 2025 Annual Meeting of Stockholders. The press release was first
used or made available on May 8, 2025.

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

Responds to Recent Public Stockholder Communications

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

Lexington, Mass., May 8, 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