SELLAS Life Sciences Group (SLS) Proxy Filing summary

Executive summary

• The 2025 Annual Meeting will be held virtually on June 17, 2025, with voting on six key proposals, including director elections, auditor ratification, an employee stock purchase plan amendment, executive compensation, say-on-pay frequency, and potential adjournment.

• Only stockholders of record as of April 22, 2025, are eligible to vote, with 94,548,425 shares outstanding and entitled to one vote per share.

• Proxy materials are distributed primarily online to conserve resources and reduce costs, with options for voting by internet, phone, or mail.

Voting matters and shareholder proposals

• Proposal 1: Election of two Class III directors (Angelos M. Stergiou and John Varian) for three-year terms expiring in 2028.

• Proposal 2: Ratification of Moss Adams LLP as independent auditor for fiscal year 2025.

• Proposal 3: Amendment to the 2021 Employee Stock Purchase Plan to add 800,000 shares.

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

• Proposal 5: Non-binding advisory vote on the frequency of future say-on-pay votes, with the board recommending annual votes.

• Proposal 6: Approval of any adjournment of the meeting to solicit additional proxies if needed.

Board of directors and corporate governance

• The 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, each with defined charters and independent membership.

• The board adopted a clawback policy for incentive-based compensation, updated in 2023 to comply with SEC and Nasdaq rules.

• Stock ownership guidelines require executives and directors to hold significant equity, with compliance expected by October 2028.