SCHEDULE 13D/A 0001953093 XXXXXXXX LIVE 1 Common Stock, par value $0.0001 per share 08/14/2025 false 0001738021 20454B104 Compass Therapeutics, Inc.

80 Guest St. Suite 601 Boston MA 02135

Commander Aggregator, LP (302) 658-7581 c/o The Corporation Trust Company Corporation Trust Cntr, 1209 Orange St. Wilmington, New Castle DE 19801 Sophia Hudson, P.C. (212) 446-4800 601 Lexington Avenue New York NY 10022 0001953093 N Commander Aggregator, LP OO N DE 0 7788150 0 7788150 7788150 N 4.5 PN Percentage of ownership is based upon 171,572,498 shares of common stock, par value $0.0001 per share ("Common Stock"), issued and outstanding, effective as of August 14, 2025, as set forth in the Issuer's Prospectus filed pursuant to Rule 424(b)(5) ("Prospectus") with the Securities and Exchange Commission ("SEC") on August 13, 2025. 0001953098 N Enavate Sciences, LP OO N DE 0 7788150 0 7788150 7788150 N 4.5 PN Percentage of ownership is based upon 171,572,498 shares of Common Stock issued and outstanding, effective as of August 14, 2025, as set forth in the Issuer's Prospectus filed with the SEC on August 13, 2025. 0001953107 N Enavate Sciences GP, LLC OO N DE 0 7788150 0 7788150 7788150 N 4.5 OO Percentage of ownership is based upon 171,572,498 shares of Common Stock issued and outstanding, effective as of August 14, 2025, as set forth in the Issuer's Prospectus filed with the SEC on August 13, 2025. Y Enavate Sciences Holdings, LLC OO N DE 0 7788150 0 7788150 7788150 N 4.5 OO Percentage of ownership is based upon 171,572,498 shares of Common Stock issued and outstanding, effective as of August 14, 2025, as set forth in the Issuer's Prospectus filed with the SEC on August 13, 2025. Common Stock, par value $0.0001 per share Compass Therapeutics, Inc. 80 Guest St. Suite 601 Boston MA 02135 This Amendment No. 1 ("Amendment No. 1") to Schedule 13D amends and supplements the initial Schedule 13D filed on November 14, 2022 (as so amended, the "Schedule 13D"). Capitalized terms used but not defined in this Amendment No. 1 shall have the same meanings ascribed to them in the Schedule 13D as amended from time to time. Item 5(a) of this Statement is hereby amended and restated in its entirety as follows: The information set forth in rows (11) and (13) of the cover pages of this Statement is incorporated by reference into this Item 5. Item 5(b) of this Statement is hereby amended and restated in its entirety as follows: The information set forth in rows (11) and (13) of the cover pages of this Statement is incorporated by reference into this Item 5. None of the Reporting Entities has effected any transactions in the Common Stock in the past 60 days. Not Applicable As a result of the decrease in the outstanding shares, effective as of August 14, 2025, as reported by the Issuer in the Prospectus filed on August 13, 2025, the Reporting Entities' beneficial ownership ceased to exceed 5% on such date and the Reporting Entities are no longer subject to Section 13 reporting. Commander Aggregator, LP /s/ James P. Boylan 08/18/2025 Enavate Sciences, LP /s/ James P. Boylan 08/18/2025 Enavate Sciences GP, LLC /s/ James P. Boylan 08/18/2025 Enavate Sciences Holdings, LLC /s/ James P. Boylan 08/18/2025 Enavate Sciences, LP By: Enavate Sciences GP, LLC Its: General Partner, Enavate Sciences GP, LLC By: Enavate Sciences Holdings, LLC Its: Sole Member