Proxy Results, Amendments to Bylaws (Form 8-K)

On May 20, 2026, TScan Therapeutics, Inc. (the "Company") held its 2026 Annual Meeting of Stockholders (the "Annual Meeting"). As further described in Item 5.07 to this Current Report on Form 8-K, at the Annual Meeting, the Company's stockholders approved an amendment to the Company's Amended and Restated Certificate of Incorporation to increase the number of authorized shares of voting common stock from 300,000,000 to 600,000,000. On May 20, 2026, the Company filed a Certificate of Amendment to the Company's Amended and Restated Certificate of Incorporation (the "Certificate of Amendment") with the Secretary of State of the State of Delaware and the Certificate of Amendment became effective upon filing. The foregoing description does not purport to be complete and is qualified in its entirety by reference to the full text of the Certificate of Amendment, a copy of which is filed as Exhibit 3.1 to this Current Report on Form 8-K and incorporated herein by reference.

On May 20, 2026, the Company held its Annual Meeting to consider and vote on the four proposals set forth below, each of which is described in greater detail in the Company's Definitive Proxy Statement on Schedule 14A, which was filed with the U.S. Securities and Exchange Commission on April 17, 2026. The final voting results are set forth below.

Proposal No. 1 - Election of Class II Directors

The stockholders of the Company elected Katina Dorton, J.D., M.B.A. and R. Keith Woods as Class II directors, each to serve for a three-year term ending at the annual meeting of stockholders to be held in 2029 and until their successor has been duly elected and qualified or until their earlier resignation or removal. The results of the stockholders' vote with respect to the election of the Class II directors were as follows:

Proposal No. 2 - Ratification of Appointment of Independent Registered Public Accounting Firm

The stockholders of the Company ratified the selection of Deloitte & Touche LLP as the Company's independent registered public accounting firm for the fiscal year ending December 31, 2026. The results of the stockholders' vote with respect to such ratification were as follows:

Proposal No. 3 - Approval of an Amendment to the Company's Amended and Restated Certificate of Incorporation

The stockholders of the Company approved an amendment to the Company's Amended and Restated Certificate of Incorporation to increase the number of authorized shares of voting common stock from 300,000,000 shares to 600,000,000 shares. The results of the stockholders' vote with respect to such approval were as follows:

Proposal No. 4 - Approval of a Proposal to Adjourn the Annual Meeting

Although Proposal No. 4 was deemed not necessary because there was a quorum present and there were sufficient proxies at the time of the Annual Meeting to approve Proposal No. 3, it was approved by the requisite vote as follows:

No other matters were submitted to or voted on by the Company's stockholders at the Annual Meeting.