Gossamer Bio, Inc. filed a Current Report on Form 8-K with the Securities and Exchange Commission on September 3, 2026, disclosing an amendment to the company's governing documents.

The filing states that the Board of Directors approved the amendment and restatement of the company's Amended and Restated Bylaws. The amendment became effective as of September 3, 2026.

The primary change involves the requirement for a quorum at meetings of stockholders. The new bylaws reduce the requisite quorum for the transaction of business from the holders of a majority of the Company's capital stock to the holders of one third (1/3) of the voting power of the Company's capital stock issued and outstanding and entitled to vote.

This change applies to meetings held in person, by remote communication, or by proxy, unless otherwise required by applicable law, the Company's certificate of incorporation, or the Amended and Restated Bylaws themselves.

A copy of the full text of the Amended and Restated Bylaws is attached to the filing as Exhibit 3.1.