Selinexor Maintenance Post CAR-T Cell Therapy for Multiple Myeloma

The outcomes in patients with relapsed multiple myeloma refractory to triple-therapy (anti-CD38, immunomodulatory drugs (IMiD) and proteasome inhibitors (PI)) remain poor. These patients are eligible for chimeric antigen receptor T-cells (CAR-T), which rely on redirecting autologous T-cells to clear myeloma cells by targeting B-cell maturation antigen (BCMA). BCMA CAR-T therapy is not curative, and unlike autologous stem cell transplant, there is currently no standard for maintenance therapy post CAR-T which could potentially increase MRD rates and extend progression-free survival. Selinexor is an exportin (XPO1) inhibitor with direct anti-tumor effect used often as an adjunct with other agents as bridging therapy prior to CAR-T. As selinexor does not affect T-cell yields or fitness, T-cell collection on selinexor for CAR-T manufacturing is safe. The aim of this study is to evaluate the safety and toxicity of selinexor in triple-exposed or refractory multiple myeloma patients with high-risk features (adverse risk cytogenetics, less than complete response (CR) post CAR-T, or extramedullary disease) following BCMA CAR-T therapy. The investigators hypothesize that selinexor as maintenance therapy following CAR-T has the potential to act synergistically with CAR-T cells leading to more durable responses.