On July 3, the U.S. Food and Drug Administration (FDA) granted accelerated approval to selinexor (Xpovio) in combination with dexamethasone for adult patients with relapsed or refractory multiple myeloma who have received at least four prior therapies and whose disease is refractory to at least two proteasome inhibitors, at least two immunomodulatory agents, and an anti-CD38 monoclonal antibody.
Richard Pazdur, MD
“While there is no cure for multiple myeloma, there are FDA-approved treatments to target the cancer and slow down the spread of the disease. Sadly, often over time, patients can exhaust all available treatments and still see their disease progress,” said Richard Pazdur, MD, Director of the FDA’s Oncology Center of Excellence and Acting Director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research. “We approved a treatment under our accelerated approval program that provides a treatment option for patients with multiple myeloma with no available therapy.”
EFFICACY WAS evaluated in 122 patients enrolled in part 2 of the STORM trial, a multicenter, single-arm, open-label study of patients with relapsed or refractory multiple myeloma who had previously received three or more antimyeloma treatment regimens, including an alkylating agent, glucocorticoids, bortezomib, carfilzomib, lenalidomide, pomalidomide, and an anti-CD38 monoclonal antibody. In addition, their disease was refractory to glucocorticoids, a proteasome inhibitor, an immunomodulatory agent, an anti-CD38 monoclonal antibody, and to the last line of therapy. These patients were treated with the recommended 80 mg of selinexor in combination with 20 mg of dexamethasone taken orally on days 1 and 3 of every week.
Results and Toxicity
THE APPROVAL was based on efficacy and safety in a prespecified subgroup analysis of 83 patients whose disease was refractory to bortezomib, carfilzomib, lenalidomide, pomalidomide, and daratumumab. The overall response rate was 25% (95% confidence interval [CI] = 16%–36%), with 1 stringent complete response, 0 complete responses, 4 very good partial responses, and 16 partial responses. The median time to first response was 4 weeks (range = 1–10 weeks). The median response duration was 3.8 months (95% CI = 2.3 months to not estimable). The efficacy evaluation was supported by additional information from an ongoing, randomized trial in patients with multiple myeloma.
Common adverse reactions reported in at least 20% of patients included thrombocytopenia, fatigue, nausea, anemia, decreased appetite, decreased weight, diarrhea, vomiting, hyponatremia, neutropenia, leukopenia, constipation, dyspnea, and upper respiratory tract infection. ■