XPOVIO (selinexor) - (XPORT-EC-042)

July 30, 2026: Karyopharm Therapeutics (NASDAQ: KPTI) reported topline Phase 3 XPORT-EC-042 results for selinexor as maintenance-only therapy versus placebo in adults with TP53 wild-type advanced or recurrent endometrial cancer. The trial did not meet its primary endpoint of progression-free survival.

In the modified intent-to-treat population (n=236), median PFS was 12.75 months with selinexor versus 7.43 months with placebo, a 5.3-month difference, with HR 0.76 (95% CI: 0.51-1.12) and one-sided p=0.0791. The company said safety and tolerability were consistent with selinexor’s known profile, with no new safety signals.

XPORT-EC-042 (NCT05611931) enrolled 257 patients globally and evaluated once-weekly oral selinexor 60 mg versus placebo after chemotherapy or chemotherapy plus a checkpoint inhibitor. Overall survival is a key secondary endpoint, and Karyopharm said it will continue following patients for longer-term outcomes and plans to present full data at a future medical meeting.

Following these results, Karyopharm said it will reduce planned investment in endometrial cancer and prioritize myelofibrosis and multiple myeloma. Upcoming myelofibrosis catalysts expected in 2H 2026 include an sNDA submission, possible compendia guideline inclusion, and topline data from the 60 mg cohort of the Phase 2 SENTRY-2 trial.