Cabaletta Bio (CABA) Proxy filing summary

Executive summary

• Annual Meeting scheduled for June 9, 2026, with participation via live webcast.

• Supplement updates the original proxy statement filed on April 28, 2026.

• Record date for voting eligibility is April 20, 2026.

Voting matters and shareholder proposals

• Proposal 3, regarding an amendment to the 2019 Stock Option and Incentive Plan, has been withdrawn and will not be considered.

• All other proposals (1, 2, 4, 5, and 6) remain on the agenda and will be voted as directed.

• Proxy cards or instructions for Proposal 3 will not be counted; no need to resubmit proxies unless changing votes on remaining proposals.

Board of directors and corporate governance

• Board decided to withdraw Proposal 3 after discussions with management and advisors.

• Board reserves the right to propose future amendments to the equity compensation plan.