Please wait

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 0001104659-25-034310 0001940272 XXXXXXXX LIVE 2 Common Stock, $0.0001 par value per share 05/08/2025 false 0001664710 492327101 Keros Therapeutics, Inc. 1050 Waltham Street, Suite 302 Lexington MA 02421 Daniel Schneeberger (512) 254-3790 3503 Wild Cherry Drive, Building 9 Austin TX 78738 0001940272 N ADAR1 Capital Management, LLC b AF N TX 5390964.00 0.00 5390964.00 0.00 5390964.00 Y 13.27 OO The amounts reported in boxes 7, 9 and 11 include (i) 4,392,737 shares of Common Stock held by ADAR1 Partners, LP, (ii) 743,558 shares of Common Stock held by Spearhead Insurance Solutions IDF, LLC and (iii) 254,669 shares of Common Stock held by ADAR1 SPV I, LP as of May 8, 2025. 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. Amounts reported do not include shares underlying certain put options and swap arrangements as disclosed in the Schedule 13D. The percentage in box 13 is based on 40,615,414 shares of Common Stock of the Issuer outstanding as of May 1, 2025, reported in the Issuer's Quarterly Report on Form 10-Q for the quarterly period ended March 31, 2025, filed with the SEC on May 6, 2025. Y ADAR1 Capital Management GP, LLC b AF N TX 4647406.00 0.00 4647406.00 0.00 4647406.00 Y 11.44 OO The amounts reported in boxes 7, 9 and 11 include (i) 4,392,737 shares of Common Stock held by ADAR1 Partners, LP and (ii) 254,669 shares of Common Stock held by ADAR1 SPV I, LP as of May 8, 2025. 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. Amounts reported do not include shares underlying certain put options and swap arrangements as disclosed in the Schedule 13D. The percentage in box 13 is based on 40,615,414 shares of Common Stock of the Issuer outstanding as of May 1, 2025, reported in the Issuer's Quarterly Report on Form 10-Q for the quarterly period ended March 31, 2025, filed with the SEC on May 6, 2025. Y Daniel Schneeberger b AF N TX 5390964.00 0.00 5390964.00 0.00 5390964.00 Y 13.27 IN The amounts reported in boxes 7, 9 and 11 include (i) 4,392,737 shares of Common Stock held by ADAR1 Partners, LP, (ii) 743,558 shares of Common Stock held by Spearhead Insurance Solutions IDF, LLC and (iii) 254,669 shares of Common Stock held by ADAR1 SPV I, LP as of May 8, 2025. 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. Amounts reported do not include shares underlying certain put options and swap arrangements as disclosed in the Schedule 13D. The percentage in box 13 is based on 40,615,414 shares of Common Stock of the Issuer outstanding as of May 1, 2025, reported in the Issuer's Quarterly Report on Form 10-Q for the quarterly period ended March 31, 2025, filed with the SEC on May 6, 2025. Common Stock, $0.0001 par value per share Keros Therapeutics, Inc. 1050 Waltham Street, Suite 302 Lexington MA 02421 This Amendment No. 2 ("Amendment No. 2") amends and supplements the statement on Schedule 13D filed with the Securities and Exchange Commission on April 11, 2025 (as amended from time to time, the "Schedule 13D"). Except as otherwise stated, the Schedule 13D remains unchanged. Capitalized terms used herein and not otherwise defined in this Amendment No. 2 have the meanings set forth in the Schedule 13D. On May 8, 2025, ADAR1 Capital Management issued a press release (the "May 8 Press Release") including an open letter (the "Letter") announcing its intention to vote "WITHHOLD" on the re-election of Dr. Mary Ann Gray and Dr. Alpna Seth at the Annual Meeting scheduled to take place on June 4, 2025. The foregoing descriptions of the May 8 Press Release and the Letter do not purport to be complete and are qualified in their entirety by reference to the full texts of the May 8 Press Release and the Letter, which are attached hereto as Exhibit D and Exhibit E, respectively, and are incorporated herein by reference. Exhibit D: May 8 Press Release Exhibit E: The Letter ADAR1 Capital Management, LLC /s/ Daniel Schneeberger Daniel Schneeberger, Manager 05/08/2025 ADAR1 Capital Management GP, LLC /s/ Daniel Schneeberger Daniel Schneeberger, Manager 05/08/2025 Daniel Schneeberger /s/ Daniel Schneeberger Daniel Schneeberger 05/08/2025