On December 7, 2023, the Board of Directors (the "Board") of Assembly Biosciences, Inc. (the "Company") appointed Tomas Cihlar, Ph.D., a designee of Gilead Sciences, Inc. ("Gilead"), to serve on the Board. Dr. Cihlar is Gilead's Senior Vice President, Virology and has been designated for appointment to the Board pursuant to the previously announced Investor Rights Agreement entered into between the Company and Gilead on October 15, 2023. Dr. Cihlar will not receive any compensation for his service as a member of the Company's Board.