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SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Name of Issuer)

(Title of Class of Securities)

(CUSIP Number)

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

SCHEDULE 13D/A 0001726334 XXXXXXXX LIVE 2 Common Stock, Par Value $0.0001 Per Share 10/15/2025 false 0001664710 492327101 Keros Therapeutics, Inc. 1050 WALTHAM STREET, SUITE 302 LEXINGTON MA 02421 Asaf Shinar 972-9-9725617 Pontifax 14 Shenkar Street Herzliya Pituach L3 4672514 0001726334 N Pontifax Management 4 GP (2015) Ltd. OO N L3 0.00 0.00 0.00 0.00 0.00 N 0 CO Y Pontifax (Israel) IV, L.P. OO N L3 0.00 0.00 0.00 0.00 0.00 N 0 PN Y Pontifax (Cayman) IV, L.P. OO N E9 0.00 0.00 0.00 0.00 0.00 N 0 PN Y Pontifax (China) IV, L.P. OO N E9 0.00 0.00 0.00 0.00 0.00 N 0 PN Y Pontifax Late Stage Fund L.P. OO N E9 0.00 0.00 0.00 0.00 0.00 N 0 PN Y Pontifax Late Stage GP Ltd. OO N L3 0.00 0.00 0.00 0.00 0.00 N 0 CO Common Stock, Par Value $0.0001 Per Share Keros Therapeutics, Inc. 1050 WALTHAM STREET, SUITE 302 LEXINGTON MA 02421 Item 3 is hereby amended and restated to read as follows: As described in Items 4 and 5 below, the Reporting Persons no longer beneficially own any shares of Common Stock. Item 4 is hereby amended and supplemented with the addition of the following: On October 15, 2025, certain of the Reporting Persons (collectively, the "Pontifax Parties") and the Issuer entered into a Stock Purchase Agreement (the "Repurchase Agreement"). Pursuant to the Repurchase Agreement, the Pontifax Parties agreed to sell a total of 4,787,331 shares of Common Stock, representing all the shares of Common Stock owned by the Reporting Persons, at a per share price of $17.75, for an aggregate price of $84,975,125.25. Pursuant to the Repurchase Agreement, the Pontifax Parties also agreed to certain standstill restrictions and voting commitments during the Standstill Period (as defined in the Repurchase Agreement), including, among other things, a restriction on the ability of the Pontifax Parties to acquire more than 100,000 shares of Common Stock (subject to certain limited exceptions and adjustments). The Issuer and the Pontifax Parties have also agreed to certain mutual non-disparagement obligations that remain in effect during the Standstill Period. In addition, concurrently with the execution of the Repurchase Agreement, each of Tomer Kariv and Ran Nussbaum, affiliates of the Pontifax Parties, delivered their resignations from the Issuer's board of directors and all committees thereof. The foregoing description of the Repurchase Agreement does not purport to be complete and is qualified in its entirety by reference to the full text of the Repurchase Agreement, which is attached as Exhibit 99.1 hereto and is incorporated herein by reference. Item 5(a) is hereby amended and restated to read as follows: As described in Item 4 above, the Reporting Persons no longer beneficially own any shares of Common Stock. Item 5(c) is hereby amended and restated to read as follows: Except as set forth in Item 4 above, the Reporting Persons have not entered into any transactions in the securities of the Issuer during the past 60 days. Item 5(e) is hereby amended and restated to read as follows: As of October 15, 2025, the Reporting Persons ceased to be the beneficial owners of more than 5% of the outstanding shares of Common Stock. Item 6 is hereby amended and supplemented with the addition of the following: On October 15, 2025, the Pontifax Parties and the Issuer entered into the Repurchase Agreement as defined and described in Item 4 above and attached as Exhibit 99.1 hereto. Item 7 is hereby amended and supplemented with the addition of the following to the Exhibit Index: 99.1 - Stock Purchase Agreement, dated October 15, 2025, by and among the Issuer and the Pontifax Parties (incorporated by reference to Ex. 2.2 to the Issuer's Current Report on Form 8-K, filed with the SEC on October 15, 2025). Pontifax Management 4 GP (2015) Ltd. /s/ Tomer Kariv Tomer Kariv, Chief Executive Officer 10/16/2025 Pontifax (Israel) IV, L.P. /s/ Tomer Kariv Tomer Kariv, Chief Executive Officer 10/16/2025 Pontifax (Cayman) IV, L.P. /s/ Tomer Kariv Tomer Kariv, Chief Executive Officer 10/16/2025 Pontifax (China) IV, L.P. /s/ Tomer Kariv Tomer Kariv, Chief Executive Officer 10/16/2025 Pontifax Late Stage Fund L.P. /s/ Asaf Shinar Asaf Shinar, Chief Financial Officer 10/16/2025 Pontifax Late Stage GP Ltd. /s/ Asaf Shinar Asaf Shinar, Chief Financial Officer 10/16/2025