A Phase 1/3 Study to Evaluate Efficacy and Safety of Selinexor, a Selective Inhibitor of Nuclear Export, in Combination With Ruxolitinib in Treatment-naïve Patients With Myelofibrosis

This is a global, multicenter Phase 1/3 study to evaluate the efficacy and safety of selinexor plus ruxolitinib in JAK inhibitor (JAKi) treatment-naïve myelofibrosis (MF) participants. The study will be conducted in two phases: Phase 1 (open-label) and Phase 3 (double-blind). Phase 1 (enrollment completed) was an open-label evaluation of the safety and recommended dose (RD) of selinexor in combination with ruxolitinib and included a dose escalation using a standard 3+3 design (Phase 1a) and a dose expansion part (Phase 1b). In Phase 3, JAKi treatment-naïve MF participants are enrolled in 2:1 ratio to receive the combination therapy of selinexor + ruxolitinib or the combination of placebo + ruxolitinib.