Brian Atwood notified Five Prime Therapeutics, Inc. of his decision to resign from the Board of Directors of FivePrime (the Board) effective March 11, 2016. Mr. Atwood's resignation from the Board is not due to any disagreement with FivePrime on any matter relating to FivePrime's operations, policies or practices. On March 15, 2016, the Board appointed (i) Lewis T. Williams, FivePrime's President and Chief Executive Officer, to the position of Chairman of the Board; and (ii) Mark McDade, a member of the Board, to the position of Lead Independent Director.