SELLAS Life Sciences Group (SLS) Proxy filing summary

Executive summary

• The 2026 Annual Meeting will be held virtually on June 16, 2026, with voting on five key proposals, including director elections, auditor ratification, equity plan amendment, executive compensation, and meeting adjournment flexibility.

• Proxy materials are distributed electronically to conserve resources and reduce costs, with voting available online, by phone, or by mail.

• Only stockholders of record as of April 21, 2026, are eligible to vote, with 184,532,574 shares outstanding.

Voting matters and shareholder proposals

• Proposal 1: Election of two Class I directors (Robert Van Nostrand and Jane Wasman) for a three-year term expiring in 2029.

• Proposal 2: Ratification of Baker Tilly US, LLP as independent auditor for fiscal year 2026.

• Proposal 3: Amendment to the 2023 Equity Incentive Plan to add 20,000,000 shares for future awards.

• Proposal 4: Non-binding advisory vote on executive compensation (say-on-pay).

• Proposal 5: Approval for potential adjournment of the meeting to solicit additional proxies if needed.

• Board recommends voting FOR all proposals.

Board of directors and corporate governance

• Board consists of six members divided into three classes, with staggered three-year terms.

• Majority of directors are independent per Nasdaq standards; John Varian serves as independent Chair since June 2024.

• Board committees include Audit, Compensation, Nominating and Corporate Governance, and Science Committees, all with independent chairs.

• Corporate Governance Guidelines, a clawback policy, and stock ownership guidelines are in place.

• Directors attended 100% of regular board meetings in 2025.