On February 22, 2017, Stephen A. Sherwin, M.D. notified Rigel Pharmaceuticals, Inc. of his decision to resign as a member of the Board of Directors of the company, effective as of May 11, 2017, the anticipated date of the company's 2017 Annual Meeting of Stockholders. At the time of Dr. Sherwin's resignation, he was an independent director and member of the Audit Committee, Governance Committee and Scientific and Clinical Trial Advisory Committee of the Board. Dr. Sherwin indicated that his decision to resign was not a result of any disagreement with the Company on any matter relating to the Company's operations, policies or practices. Effective upon Dr. Sherwin's resignation, the Board also appointed Gary A. Lyons, a current member of the Board, to the Audit Committee of the Board (the Audit Committee). Mr. Lyons's appointment to the Audit Committee fills the vacancy created by the resignation of Dr. Sherwin.