On June 1, 2021, Blake Byers, Ph.D., notified Magenta Therapeutics, Inc. of his intent to resign from the Company's Board of Directors and from his position as member of the Nominating and Corporate Governance Committee of the Board, effective June 1, 2021. Dr. Byers' decision to resign from the Board was not the result of any dispute or disagreement with the Company or the Company's Board on any matter relating to the Company's operations, policies or practices.