Company: KROS
Filing Date: 2025-04-23
Form Type: DEFA14A
Source: 0001104659-25-037995
Chunk: 0

Company: Keros Therapeutics, Inc.
Filing Date: 2025-04-23
Form: DEFA14A
Chunk 0
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<div align='center'>SCHEDULE 14A INFORMATION

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934

(Amendment No. )</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 Rules 14a-6(i)(1) and 0-11. |