Company: KROS
Filing Date: 2025-05-27
Form Type: DEFA14A
Source: 0001104659-25-052890
Chunk: 0

Company: Keros Therapeutics, Inc.
Filing Date: 2025-05-27
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 the recommendation by leading independent proxy advisory firm Glass
Lewis & Co. (“Glass Lewis”) that that Keros stockholders vote “FOR” all three of the Company’s highly
qualified director nominees in connection with its Annual Meeting of Stockholders. The press release was first used or made available
on May 27, 2025.

<div align='center'>Leading Independent Proxy Advisory Firm Glass Lewis Recommends Stockholders Vote “FOR” All of
Keros’ Director Nominees

Keros Board Best Equipped to Oversee Strategic Review Process and
Execute on Ultimate Outcome of that Process

ADAR1’s Disruptive and Self-Serving Campaign Stands to Jeopardize the Future Value Maximizing
Potential of the Company

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

Lexington, Mass., May 27,