SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* Pontifax Management 4 G.P. (2015) Ltd. (Last) (First) (Middle) 14 SHENKAR STREET, BEIT OFEK (Street) HERZLIYA PITUACH L3 46140 (City) (State) (Zip)	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)
	3. Date of Earliest Transaction (Month/Day/Year) 11/29/2022
	4. If Amendment, Date of 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

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	11/29/2022		X(1)		3,539	D	$0.0001	2,284,612	I	See footnote(2)
Common Stock	11/29/2022		X(1)		1,723	D	$0.0001	1,121,045	I	See footnote(3)
Common Stock	11/29/2022		X(1)		1,914	D	$0.0001	1,226,412	I	See footnote(4)

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 Securities Underlying Derivative Security (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: 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
Call Options (obligation to sell)	$0.0001	11/29/2022		X(1)			3,539	(5)	10/07/2023	Common Stock	3,539	$0.00	0	I	See footnote(2)
Call Options (obligation to sell)	$0.0001	11/29/2022		X(1)			1,723	(5)	10/07/2023	Common Stock	1,723	$0.00	0	I	See footnote(3)
Call Options (obligation to sell)	$0.0001	11/29/2022		X(1)			1,914	(5)	10/07/2023	Common Stock	1,914	$0.00	0	I	See footnote(4)

1. Name and Address of Reporting Person* Pontifax Management 4 G.P. (2015) Ltd. (Last) (First) (Middle) 14 SHENKAR STREET, BEIT OFEK (Street) HERZLIYA PITUACH L3 46140 (City) (State) (Zip)

1. Name and Address of Reporting Person* Pontifax (Israel) IV, L.P. (Last) (First) (Middle) 14 SHENKAR STREET, BEIT OFEK (Street) HERZLIYA PITUACH L3 46140 (City) (State) (Zip)

1. Name and Address of Reporting Person* Pontifax (Cayman) IV L.P. (Last) (First) (Middle) 14 SHENKAR STREET, BEIT OFEK (Street) HERZLIYA PITUACH L3 46140 (City) (State) (Zip)

1. Name and Address of Reporting Person* Pontifax (China) IV L.P. (Last) (First) (Middle) 14 SHENKAR STREET, BEIT OFEK (Street) HERZLIYA PITUACH L3 46140 (City) (State) (Zip)

1. Name and Address of Reporting Person* Pontifax Late Stage Fund L.P. (Last) (First) (Middle) 14 SHENKAR STREET, BEIT OFEK (Street) HERZLIYA PITUACH L3 46140 (City) (State) (Zip)

1. Name and Address of Reporting Person* Pontifax Late Stage GP Ltd. (Last) (First) (Middle) 14 SHENKAR STREET, BEIT OFEK (Street) HERZLIYA PITUACH L3 46140 (City) (State) (Zip)

Explanation of Responses:

1. Represents an exercise of a call option (obligation to sell), pursuant to a stock option agreement dated January 21, 2016, by and between the Pontifax (Israel) IV, L.P. ("Israel IV"), Pontifax (Cayman) IV, L.P. ("Cayman IV") and Pontifax (China) IV, L.P. ("China IV") and a certain securityholder.

2. The securities are held by Israel IV. Pontifax Management 4 G.P. (2015) Ltd. ("Management 4") is the ultimate general partner of Israel IV. As a result Management 4 may be deemed to share voting and dispositive power with respect to the shares held by Israel IV. Management 4 disclaims beneficial ownership of such shares, except to the extent of its pecuniary interest therein, and the inclusion of the shares in this report shall not be deemed to be an admission of beneficial ownership of the reported shares for purposes of Section 16 of the Securities Exchange Act of 1934 or otherwise.

3. The securities are held by Cayman IV. Management 4 is the ultimate general partner of Cayman IV. As a result Management 4 may be deemed to share voting and dispositive power with respect to the shares held by Cayman IV. Management 4 disclaims beneficial ownership of such shares, except to the extent of its pecuniary interest therein, and the inclusion of the shares in this report shall not be deemed to be an admission of beneficial ownership of the reported shares for purposes of Section 16 of the Securities Exchange Act of 1934 or otherwise.

4. The securities are held by China IV. Management 4 is the ultimate general partner of China IV. As a result Management 4 may be deemed to share voting and dispositive power with respect to the shares held by China IV. Management 4 disclaims beneficial ownership of such shares, except to the extent of its pecuniary interest therein, and the inclusion of the shares in this report shall not be deemed to be an admission of beneficial ownership of the reported shares for purposes of Section 16 of the Securities Exchange Act of 1934 or otherwise.

5. Fully vested and exercisable.

Remarks:

	/s/ Keith Regnante, Attorney-in-Fact for Pontifax Management 4 G.P. (2015) Ltd.	11/30/2022
	/s/ Keith Regnante, Attorney-in-Fact for Pontifax (Israel) IV L.P.	11/30/2022
	/s/ Keith Regnante, Attorney-in-Fact for Pontifax (Cayman) IV L.P.	11/30/2022
	/s/ Keith Regnante, Attorney-in-Fact for Pontifax (China) IV L.P.	11/30/2022
	/s/ Keith Regnante, Attorney-in-Fact for Pontifax Late Stage Fund, L.P.	11/30/2022
	/s/ Keith Regnante, Attorney-in-Fact for Pontifax Late Stage GP Ltd.	11/30/2022
	** Signature of Reporting Person	Date
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