Karyopharm to Host Investor Conference Call Featuring Expert Perspectives on the Phase 3 SENTRY Trial in Myelofibrosis Following 2026 ASCO Presentation

– Event To Feature Dr. John Mascarenhas, Principal Investigator of the Phase 3 SENTRY Trial –

– Conference Call Scheduled for Tuesday, June 2, 2026 at 2:00 p.m. ET–

NEWTON, Mass.,June 1, 2026/PRNewswire/ -- Karyopharm Therapeutics Inc. (Nasdaq:KPTI), a commercial-stage pharmaceutical company pioneering novel cancer therapies, today announced that it will host a conference call on June 2, 2026 at 2:00 p.m. ET featuring the Company's senior management team and Dr. John Mascarenhas, Professor of Medicine at the Icahn School of Medicine at Mount Sinai and Director of the Center of Excellence for Blood Cancers and Myeloid Disorders, and principal investigator of the Phase 3 SENTRY trial. The call will discuss the results from the Phase 3 SENTRY trial of selinexor plus ruxolitinib in myelofibrosis and will follow Dr. Mascarenhas' oral presentation of the results at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting.

To access the conference call, please dial (800) 836-8184 (local) or (646) 357-8785 (international) at least 10 minutes prior to the start time and ask to be joined into the Karyopharm Therapeutics call. A live audio webcast of the call, along with accompanying slides, will be available under "Events & Presentations" in the Investor section of the Company's website,http://investors.karyopharm.com/events-presentations. An archived webcast will be available on the Company's website approximately two hours after the event.

Karyopharm Therapeutics is a commercial-stage pharmaceutical company pioneering the science of nuclear export inhibition to develop differentiated therapies for patients with cancer. The Company's lead therapy, XPOVIO® (selinexor), is a first-in-class inhibitor of exportin 1 (XPO1). XPOVIO is marketed by the Company in the U.S. for adults with relapsed or refractory multiple myeloma and is approved as XPOVIO or NEXPOVIO® in more than 50 ex-U.S. countries and territories. Building on its leadership in XPO1 biology, Karyopharm is advancing selinexor's potential in hematologic and solid tumor cancers, including in myelofibrosis and TP53 wild-type endometrial cancer. The Company is also exploring opportunities to evaluate XPO1 inhibition across myeloproliferative neoplasms and TP53 wild-type driven solid tumors using next-generation compounds, including eltanexor. Headquartered in Newton, Massachusetts, Karyopharm has an established, efficient and scalable commercial infrastructure to bring novel therapeutic options to patients with cancer. For more information, visitwww.karyopharm.comand follow Karyopharm onLinkedInand on X at @Karyopharm.

XPOVIO®and NEXPOVIO®are registered trademarks of Karyopharm Therapeutics Inc.