 Encouraging Initial Data Observed in Phase 12 Study of Selinexor in Combination with Ruxolitinib in Treatment-Naïve Myelofibrosis, Including Favorable Tolerability with No Dose Limiting Toxicities and 75 of Evaluable Patients Demonstrating 35 Spleen Volume Reduction SVR 35 at Week 12 FDA Grants Orphan Drug Designation for Selinexor for the Treatment of Myelofibrosis Exploratory Subgroup Analyses from SIENDO Trial in Patients with Endometrial Cancer Treated with Selinexor as Maintenance Therapy Identified p53 Wild-type as a Potentially Important Predictor of Efficacy, with 10-month PFS Improvement over Placebo; No Benefit Was Seen in Patients with p53 Mutant Tumors NEWTON, Mass., May 26, 2022 PRNewswire -- Karyopharm Therapeutics Inc. Nasdaq: KPTI, a commercial-stage pharmaceutical company pioneering novel cancer therapies, today announced promising initial data from a Phase 12 study evaluating selinexor in combination with ruxolitinib in patients with treatment-naïve myelofibrosis and subgroup analyses and molecular classification data from the SIENDO study evaluating selinexor in endometrial cancer. 