FDA Approves Selinexor for use After First Line Multiple Myeloma Therapy

The FDA approved today the use of the oral drug XPOVIO® (Selinexor) as a treatment for multiple myeloma patients who have relapsed after their first line of therapy. The approval comes three months early from the anticipated approval date. 

The approval opens the door for XPOVIO to be used in the only once-weekly combination with bortezomib (Velcade) and dexamethasone. The announcement makes selinexor the first FDA approval since 2016 for a drug with a new mechanism of action to be approve for second line therapy.

"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.

The approval is based in part on the BOSTON study results - a Phase 3 study of 402 relapsed or refractory myeloma patients from over 150 clinics who had received between one and three prior lines of therapy. The BOSTON study compared the triple combination of selinexor/bortezomib/low-dose dex vs. once weekly bortezomib/low-dose dex.

The study included more than 50% of patients with high risk genetic features. The median progression free survival in the SVd arm was 13.9 months compared to 9.5 months in the Vd. The overall response rate was 76.4% in the SVd arm vs. 62.3% in the Vd arm. 

Responses were deeper in the SVd arm vs. the Vd arm with 17% of patients achieving a complete response (CR) or stringent complete response (sCR) compared to 10% patients in the Vd arm.

The median duration of response was was longer in the SVd arm (20.3 months) vs. the Vd arm (12.9 months). 

One of the most interesting points about the combination is that the addition of selinexor to Velcade and dex lowers peripheral neuropathy (SVd at 32% vs. Vd at 47%). For more severe peripheral neuropathy (over Grade 2), rates were lower in the SVd arm (21%) vs. the Vd arm (34%). 

Side effects included lower blood counts and gastrointestinal issues, which are previously known from other selinexor studies and require supportive care. 

The full results from the BOSTON study were recently published in The Lancet and can be found here.

The unique features of an all-oral and weekly combination with lowered neuropathy when combined with Velcade and effective for high risk patients is a unique combination that will be helpful for relapsed myeloma patients. 

Dr. Richardson continued: 

"As the only approved nuclear export inhibitor that has demonstrated a strong synergistic effect with a proteasome inhibitor such as bortezomib, selinexor has, in my opinion, the potential to meet a current treatment gap for our multiple myeloma patients in need of new therapeutic options."

To read the entire press release, click here.