The FDA has recently expanded approval for selinexor (XpovioTM, Karyopharm Therapeutics) to include combination therapy with bortezomib and dexamethasone for adults with multiple myeloma who have received at least one previous line of therapy. Previously, selinexor was approved in combination with dexamethasone for patients with multiple myeloma who have received four previous lines of therapy, including two proteasome inhibitors, at least two immunomodulatory agents, and an anti-CD38 monoclonal antibody.
Approval was based on BOSTON (NCT03110562), a phase 3, open-label trial that enrolled 402 patients with multiple myeloma who had received one to three prior lines of therapy, including proteasome inhibitors. Patients were randomized in a 1:1 ratio to receive selinexor 100 mg once per week, bortezomib 1.3 mg/m2 once per week, and dexamethasone 20 mg twice per week, or the control treatment of bortezomib, 1.3 mg/m2 twice per week for the first 24 weeks and twice per week thereafter, and dexamethasone, 20 mg four times per week for the first 24 weeks and twice per week thereafter.
After a median follow up of 13.2 months for the selinexor/bortezomib/dexamethasone group and 16.5 months for the bortezomib/dexamethasone group, results revealed that median progression-free survival was higher for patients receiving selinexor/bortezomib/dexamethasone compared with those receiving bortezomib/dexamethasone alone (13.93 months vs 9.46 months).
Thrombocytopenia was the most common adverse event reported and occurred in 39% of patients in the selinexor/bortezomib/dexamethasone group. Anemia, fatigue, and pneumonia were the next most common treatment-related side effects, occurring in 17%, 13%, and 11%, respectively, of patients in the selinexor/bortezomib/dexamethasone group.
"New treatments for multiple myeloma remain a critical need for both patients and their treating physicians," stated Paul Richardson, MD, Clinical Program Leader and Director of Clinical Research for the Jerome Lipper Multiple Myeloma Center at Dana-Farber Cancer Institute and co-senior author of the BOSTON study publication in The Lancet. "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."
For More Information
Grosicki S, Simonova M, Spicka I, et al (2020). Once-per-week selinexor, bortezomib, and dexamethasone versus twice-per-week bortezomib and dexamethasone in patients with multiple myeloma (BOSTON): a randomized, open-label, phase 3 trial. Lancet, 396(10262):1563-1573. DOI:10.1016/S0140-6736(20)32292-3
US Food & Drug Administration (2020). FDA approves selinexor for refractory or relapsed multiple myeloma. Available at: https://www.fda.gov/drugs/drug-approvals-and-databases/fda-approves-selinexor-refractory-or-relapsed-multiple-myeloma
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