Submission of Matters to a Vote of Security Holders Form 8 K

On June 3, 2024, Cabaletta Bio, Inc. (the "Company") held its 2024 Annual Meeting of Stockholders (the "Annual Meeting"). As of April 4, 2024, the record date for the Annual Meeting, there were 46,804,820 outstanding shares of the Company's voting common stock, par value $0.00001 per share (the "Common Stock"). The Company's stockholders voted on the following matters, which are described in detail in the Company's definitive proxy statement on Schedule 14A (the "Proxy Statement"): (i) to elect two directors, Catherine Bollard, MBChB, M.D., and Richard Henriques, MBA, as Class II directors of the Company, each to serve for a three-year term expiring at the Company's 2027 annual meeting of stockholders and until their successor has been duly elected and qualified, subject to their earlier death, resignation or removal ("Proposal 1") and (ii) to ratify the appointment of Ernst & Young LLP as the Company's independent registered public accounting firm for the fiscal year ending December 31, 2024 ("Proposal 2").

The Company's stockholders approved the Class II director nominees, Catherine Bollard, MBChB, M.D., and Richard Henriques, MBA, recommended for election in Proposal 1 at the Annual Meeting. The votes cast at the Annual Meeting were as follows:

The Company's stockholders ratified the appointment of Ernst & Young LLP as the Company's independent registered public accounting firm for the fiscal year ending December 31, 2024, recommended for ratification in Proposal 2 at the Annual Meeting. The votes cast at the Annual Meeting were as follows:

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