Sionna Therapeutics (SION) Proxy filing summary

Voting matters and shareholder proposals

• Four class II directors are up for election to serve until the 2029 annual meeting or until a successor is duly elected and qualified, or earlier death, resignation, or removal.

• Ratification of Deloitte & Touche LLP as the independent registered public accounting firm for the fiscal year ending December 31, 2026, is proposed.

• Proxies are authorized to vote on any other business that may properly come before the meeting or any adjournment.

Board of directors and corporate governance

• Director nominees include H. Edward Fleming, Jr., M.D., Marcella Kuhlman Ruddy, M.D., Peter A. Thompson, M.D., and Joanne Louise Viney, Ph.D.

Audit committee and external auditor matters

• Deloitte & Touche LLP is recommended for ratification as the independent registered public accounting firm for the 2026 fiscal year.