FDA Approves Selinexor Combination for Pretreated Patients with Myeloma

The FDA approved selinexor (Xpovio) plus bortezomib and dexamethasone for the treatment of patients with myeloma who previously had at least 1 other treatment.

"Today's U.S. approval broadens the existing label for XPOVIO and allows Karyopharm to offer a new, highly active, treatment option to a significantly expanded patient population," said Sharon Shacham, PhD, MBA, Founder, President and Chief Scientific Officer of Karyopharm, the manufacturer of the agent.

The approval was based on findings from the randomized phase 3 BOSTON study, which included 402 patients with relapsed/refractory myeloma who had 1-3 prior lines of therapy. Participants were randomized to receive the Selinexor combination (SVd) once a week or bortezomib (Velcade) plus dexamethasone (Vd) twice a week.

Median progression-free survival (PFS) in the SVd arm was 13.9 months, compared to 9.5 months in the Vd arm — a 47% increase. The SVd arm also improved the overall response rate in several subgroups, 76.4% and 62.3%, respectively.

Additionally, the SVd arm had a higher rate of deep responses than the Vd arm and had a lower rate of peripheral neuropathy.

The most common adverse events (AEs) from the selinexor regimen were cytopenia and gastrointestinal issues. Constitutional symptoms were consistent with what was previously reported on other selinexor studies, and most reactions were able to be managed with dose modifications and/or supportive care.

Common non-hematologic AEs were fatigue (59%), decreased appetite (35%), and diarrhea (32%). Common grade 3-4 AEs were thrombocytopenia (43%), lymphopenia (38%), fatigue (28%), and anemia (17%).

"New treatments for multiple myeloma remain a critical need for both patients and their treating physicians," said Paul Richardson, MD, Clinical Program Leader and Director of Clinical Research, Jerome Lipper Multiple Myeloma Center at Dana-Farber Cancer Institute and co-senior author of the BOSTON study publication.