On December 18, 2020, the U.S. Food and Drug Administration (FDA) approved selinexor (Xpovio®) in combination with bortezomib and dexamethasone for the treatment of adult patients with relapsed or refectory multiple myeloma (RRMM) who have received at least one prior therapy.
FDA granted selinexor accelerated approval in 2019 in combination with dexamethasone for the treatment of adult patients with RRMM 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.
Efficacy of selinexor in combination with bortezomib and dexamethasone was evaluated a randomized (1:1), open-label, multicenter, active comparator-controlled trial (KCP-330-023; NCT03110562) of patients with RRMM who had previously received at least one and at most three prior therapies. Patients received selinexor orally once weekly in combination with once-weekly bortezomib subcutaneous and oral low-dose dexamethasone twice weekly (SVd) compared to the standard twice-weekly bortezomib plus low-dose dexamethasone (Vd).
The main efficacy outcome measure was progression-free survival (PFS) assessed by an independent review committee using international myeloma working group response criteria. Estimated median PFS was 13.9 months (95% CI = 11.7, not estimable) for the SVd arm and 9.5 months (95% CI = 7.6, 10.8) for the Vd arm (estimated hazard ratio = 0.70; 95% CI = 0.53, 0.93).
Common adverse reactions (≥ 20%) were nausea, fatigue, decreased appetite, diarrhea, peripheral neuropathy, upper respiratory tract infection decreased weight, cataract, and vomiting. Grade 3–4 laboratory abnormalities (≥ 10%) were thrombocytopenia, lymphopenia, hypophosphatemia, anemia hyponatremia, and neutropenia. The prescribing information provides warnings and precautions for thrombocytopenia, neutropenia, gastrointestinal toxicity, hyponatremia, serious infection, neurological toxicity, embryo-fetal toxicity, and cataracts.
The recommended selinexor dose is 100 mg orally once weekly on day 1 of each week of a 35-day cycle until disease progression or unacceptable toxicity in combination with:
Bortezomib 1.3 mg/m2 administered subcutaneously once weekly on day 1 of each week for 4 weeks followed by 1 week off
Dexamethasone 20 mg taken orally twice weekly on days 1 and 2 of each week
Providers should instruct patients to swallow tablets whole and not to crush or chew them.
The application was granted regular review and orphan drug designation. A description of FDA expedited programs is in the Guidance for Industry—Expedited Programs for Serious Conditions—Drugs and Biologics.
Healthcare professionals should report all serious adverse events suspected to be associated with the use of any medicine and device to FDA’s MedWatch Reporting System or by calling 800-FDA-1088.