FDA Approves Selinexor for Refractory or Relapsed Multiple Myeloma

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On December 18, 2020, the U.S. Food and Drug Administration (FDA) approved selinexor (Xpovio) in combination with bortezomib (Velcade) and dexamethasone for the treatment of adult patients with multiple myeloma who have received at least one prior therapy.

The FDA granted selinexor accelerated approval in 2019 in combination with dexamethasone for the treatment of adult patients with relapsed or refractory multiple myeloma who 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.

Phase III BOSTON Trial

Efficacy of selinexor in combination with bortezomib and dexamethasone was evaluated in the phase III BOSTON trial, a randomized (1:1) open-label, multicenter, active comparator-controlled trial in patients with relapsed or refractory multiple myeloma who had previously received at least one and at most three prior therapies. Patients received once-weekly selinexor orally in combination with once-weekly bortezomib subcutaneous and low-dose dexamethasone twice-weekly orally compared to the standard twice-weekly bortezomib plus low-dose dexamethasone.

The main efficacy outcome measure was progression-free survival assessed by an independent review committee using International Myeloma Working Group response criteria. The estimated median progression-free survival was 13.9 months (95% confidence interval [CI] = 11.7–not estimable) for the selinexor arm and 9.5 months (95% CI = 7.6, 10.8) for the control arm (estimated hazard ratio = 0.70, 95% CI = 0.53–0.93).

Adverse Events

Common adverse reactions reported in at least 20% of patients include nausea, fatigue, decreased appetite, diarrhea, peripheral neuropathy, upper respiratory tract infection decreased weight, cataract, and vomiting. Grade 3-4 laboratory abnormalities (≥ 10%) are thrombocytopenia, lymphopenia, hypophosphatemia, anemia, hyponatremia, and neutropenia.

The prescribing information provides warnings and precautions for thrombocytopenia, neutropenia, gastrointestinal toxicity, hyponatremia, serious infection, neurologic toxicity, embryo-fetal toxicity, and cataract.

For additional safety and efficacy information as well as the recommended dosing regimens, view the full prescribing information for selinexor.

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.