Karyopharm Therapeutics disclosed top-line Phase 3 results from its Sentry trial of Xpovio (selinexor) plus ruxolitinib in front-line myelofibrosis. The combination met the trial’s first co-primary endpoint with a statistically significant improvement in spleen volume reduction of 35% or more, accompanied by rapid and sustained reductions. Karyopharm reported that symptom-score changes at week 24 were similar across arms and that the second co-primary endpoint did not reach statistical significance. Still, the company said the overall survival signal appears “promising” and plans to meet with the U.S. FDA regarding a potential supplemental NDA filing. Investors will now monitor FDA positioning on endpoint acceptability, particularly where efficacy benefits appear concentrated on the spleen and not on the patient-reported symptom co-primary measure. If Karyopharm secures alignment, the next step would be formal regulatory engagement toward an sNDA strategy.