Amendments to Bylaws (Form 8-K)

Item 5.03. Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year.

On June 22, 2026, the Board of Directors (the "Board") of Compass Therapeutics, Inc. (the "Company") approved the adoption of the Second Amended and Restated Bylaws of the Company, effective as of June 22, 2026 (the "New Bylaws"), which amend and restate the Amended and Restated Bylaws of the Company, dated as of July 17, 2020 (the "Existing Bylaws"), in their entirety. The New Bylaws amended the Existing Bylaws to establish exclusive jurisdiction in the United States District Courts for the District of Delaware and District of Massachusetts for resolving any action asserting a claim arising under Securities Act of 1933, as amended.

The foregoing description of the New Bylaws does not purport to be complete and is qualified in its entirety by reference to the full text of the New Bylaws, which is filed as Exhibit 3.1 to this Current Report on Form 8-K and is incorporated herein by reference.