On March 13, 2023, the board of directors of Amylyx Pharmaceuticals, Inc. appointed Karen Firestone to fill the vacancy on the Board as a Class I director, effective as of March 16, 2023 (the “Effective Date”), for an initial term expiring at the annual meeting of stockholders in 2025. Ms. Firestone has been appointed as a member of the Audit Committee and Nominating and Corporate Governance Committee.