Sec Form 3/A Filing - Kariv Tomer @ Keros Therapeutics, Inc. - 2020-04-07

FORM 3/A Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

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, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Kariv Tomer 2. Issuer Name and Ticker or Trading Symbol Keros Therapeutics, Inc. [ KROS] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O KEROS THERAPEUTICS, INC., 99 HAYDEN AVENUE, SUITE 120, BUILDING E 3. Date of Earliest Transaction (MM/DD/YY) 04/07/2020 (Street) LEXINGTON, MA02421 4. If Amendment, Date Original Filed (MM/DD/YY) 04/07/2020 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ 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 (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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

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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 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 Call Options (obligation to sell)( 1 ) $ 0.0001 ( 2 ) 10/07/2023 Common Stock 3,539 I See footnote( 3 ) Call Options (obligation to sell)( 1 ) $ 0.0001 ( 2 ) 10/07/2023 Common Stock 1,723 I See footnote( 4 ) Call Options (obligation to sell)( 1 ) $ 0.0001 ( 2 ) 10/07/2023 Common Stock 1,914 I See footnote( 5 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Kariv Tomer C/O KEROS THERAPEUTICS, INC. 99 HAYDEN AVENUE, SUITE 120, BUILDING E LEXINGTON, MA02421 X X Signatures /s/ Keith Regnante, Attorney-in-Fact 11/30/2022 Signature of Reporting Person Date

Explanation of Responses:

( 1 )This security was inadvertently omitted from the Original Form 3. ( 2 )Fully vested and exercisable. ( 3 )The securities are held by Pontifax (Israel) IV, L.P. ("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. The Reporting Person, a member of the board of directors of the Issuer, is a Managing Partner of Management 4 and, as a result, may be deemed to share voting and investment power with respect to the shares held by Israel IV. Each of Management 4 and the Reporting Person 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 Pontifax (Cayman) IV, L.P. ("Cayman IV"). Management 4 is the ultimate general partner of Cayman IV. The Reporting Person, a member of the board of directors of the Issuer, is a Managing Partner of Management 4 and, as a result, may be deemed to share voting and investment power with respect to the shares held by Cayman IV. Each of Management 4 and the Reporting Person 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 )The securities are held by Pontifax (China) IV, L.P. ("China IV"). Management 4 is the ultimate general partner of China IV. The Reporting Person, a member of the board of directors of the Issuer, is a Managing Partner of Management 4 and, as a result, may be deemed to share voting and investment power with respect to the shares held by China IV. Each of Management 4 and the Reporting Person 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.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* 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).

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