Statement of Changes in Beneficial Ownership (Form 4)

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b). Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person * ADAR1 Capital Management, LLC 2. Issuer Name and Ticker or Trading Symbol Keros Therapeutics, Inc. [KROS] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director __X__ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 3503 WILD CHERRY DRIVE, BUILDING 9 3. Date of Earliest Transaction (Month/Day/Year) 04/09/2025 (Street) AUSTIN, TX 78738 4. If Amendment, Date Original Filed (Month/Day/Year) 6. Individual or Joint/Group Filing (Check Applicable Line) ___ Form filed by One Reporting Person _X_ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 04/09/2025 P 18,560 A $9.3952(2) 3,493,404 I By ADAR1 Partners, LP(1)(8) Common Stock 04/09/2025 P 16,365 A $9.3952(3) 743,558 I By Spearhead Insurance Solutions IDF, LLC(1)(8) Common Stock 04/09/2025 P/K 325,000 A $9.857(4) 3,818,404 I By ADAR1 Partners, LP(1)(8) Common Stock 04/09/2025 P/K 500,000 A $10.33 4,318,404 I By ADAR1 Partners, LP(1)(8) Common Stock 04/09/2025 P/K 74,333 A $10.33 4,392,737 I By ADAR1 Partners, LP(1)(8) Common Stock 254,669 I By ADAR1 SPV I, LP(1)(8)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Cash-Settled Total Return Swaps

(5)

04/09/2025

J(5)

325,000(5)

(5)

(5)

Common Stock

325,000(5)

(5)

624,333(5)

I

By ADAR1 Partners, LP(1)(8)

Cash-Settled Total Return Swaps

(6)

04/09/2025

J(6)

500,000(6)

(6)

(6)

Common Stock

500,000(6)

(6)

124,333(6)

I

By ADAR1 Partners, LP(1)(8)

Cash Settled Total Return Swaps

(7)

04/09/2025

J(7)

74,333(7)

(7)

(7)

Common Stock

74,333(7)

(7)

50,000(7)

I

By ADAR1 Partners, LP(1)(8)

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
ADAR1 Capital Management, LLC 3503 WILD CHERRY DRIVE BUILDING 9 AUSTIN, TX 78738		X
ADAR1 Partners, LP 3503 WILD CHERRY DRIVE BUILDING 9 AUSTIN, TX 78738		X
ADAR1 Capital Management GP, LLC 3503 WILD CHERRY DRIVE BUILDING 9 AUSTIN, TX 78738		X
Schneeberger Daniel 3503 WILD CHERRY DRIVE BUILDING 9 AUSTIN, TX 78738		X

Signatures

ADAR1 Capital Management, LLC, By /s/ Daniel Schneeberger, Manager		04/11/2025
**Signature of Reporting Person		Date
ADAR1 Partners, LP, By /s/ Daniel Schneeberger, Manager		04/11/2025
**Signature of Reporting Person		Date
ADAR1 Capital Management GP, LLC, By /s/ Daniel Schneeberger, Manager		04/11/2025
**Signature of Reporting Person		Date
/s/ Daniel Schneeberger		04/11/2025
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	As the investment manager of ADAR1 Partners, LP and ADAR1 SPV I, LP and as the sub-advisor of Spearhead Insurance Solutions IDF, LLC, ADAR1 Capital Management, LLC may be deemed to indirectly beneficially own securities held by ADAR1 Partners, LP, ADAR1 SPV I, LP and Spearhead Insurance Solutions IDF, LLC. As the general partner of ADAR1 Partners, LP and ADAR1 SPV I, LP, ADAR1 Capital Management GP, LLC may be deemed to indirectly beneficially own securities held by ADAR1 Partners, LP and ADAR1 SPV I, LP. As the manager of ADAR1 Capital Management, LLC and ADAR1 Capital Management GP, LLC, Mr. Schneeberger may be deemed to indirectly beneficially own securities held by ADAR1 Partners, LP, Spearhead Insurance Solutions IDF, LLC, and ADAR1 SPV I, LP.
(2)	The reported price is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $9.21 to $9.56, inclusive.
(3)	The reported price is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $9.21 to $9.56, inclusive.
(4)	The reported price is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $9.13 to $10.60, inclusive.
(5)	In connection with the purchase of 325,000 securities reported as being purchased in Table 1, ADAR1 Partners, LP and the counterparty to the cash-settled total equity swaps previously reported agreed to reduce the number of notional shares of Common Stock of the Issuer in the applicable basket by a corresponding number of 325,000 shares. As a result, the aggregate number of notional shares of Common Stock of the Issuer in the applicable basket after giving effect to such transactions is 624,333 shares.
(6)	In connection with the purchase of 500,000 securities reported as being purchased in Table 1, ADAR1 Partners, LP and the counterparty to the cash-settled total equity swaps previously reported agreed to reduce the number of notional shares of Common Stock of the Issuer in the applicable basket by a corresponding number of 500,000 shares. As a result, the aggregate number of notional shares of Common Stock of the Issuer in the applicable basket after giving effect to such transactions is 124,333 shares.
(7)	In connection with the purchase of 74,333 securities reported as being purchased in Table 1, ADAR1 Partners, LP and the counterparty to the cash-settled total equity swaps previously reported agreed to reduce the number of notional shares of Common Stock of the Issuer in the applicable basket by a corresponding number of 74,333 shares. As a result, the aggregate number of notional shares of Common Stock of the Issuer in the applicable basket after giving effect to such transactions is 50,000 shares.
(8)	For purposes of Section 16 of the Securities Exchange Act of 1934, as amended, each Reporting Person disclaims beneficial ownership of any such securities, except to the extent of his/its pecuniary interest therein, if any, and this report shall not be deemed an admission that such Reporting Person is the beneficial owner of such securities for purposes of Section 16 or otherwise.

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