Selinexor Treatment of Refractory Myeloma

This is a Phase 2b, single-arm, open-label, multicenter study of selinexor 80 mg plus dexamethasone 20 mg (Sd), both dosed twice weekly in each four-week cycle, in patients with MM previously treated with lenalidomide, pomalidomide, bortezomib, carfilzomib, and daratumumab and refractory to prior treatment with glucocorticoids, an immunomodulatory agent (IMiD), a proteasome inhibitor (PI), and daratumumab. This study consists of two parts: * Part 1 enrolled patients with both quad-refractory MM and penta-refractory MM. * Part 2 will enroll patients with penta-refractory MM only.