On May 25, 2021, Thomas J. Russo, CFA, principal financial officer and principal accounting officer of Assembly Biosciences, Inc. (the “Company”), notified the Company of his decision to resign effective June 4, 2021 to pursue another opportunity. Effective June 4, 2021, Michael P. Samar, the Company’s Senior Vice President, Finance and Business Operations, will serve the functions of the Company’s principal financial officer and principal accounting officer.