On December 5, 2023, Peter K Honig, M.D., MPH, a member of the Board of Directors of Karyopharm Therapeutics Inc., notified the Company of his resignation from the Board, effective as of December 31, 2023. Dr. Honig?s resignation is due to competing professional demands and not the result of any disagreement with the Company on any matter relating to the Company?s operations, policies or practices.