On November 14, 2019, the FDA granted accelerated approval to zanubrutinib capsules (Brukinsa; BeiGene), a Bruton’s tyrosine kinase (BTK) inhibitor, for the treatment of adults with mantle-cell lymphoma who have received at least 1 previous therapy. This is the second BTK inhibitor to be approved by the FDA.
“Mantle cell lymphoma usually responds well to initial treatment, but eventually returns or stops responding, and the cancer cells continue to grow. This is a life-threatening condition,” said Richard Pazdur, MD, Director of the FDA’s Oncology Center of Excellence. “Clinical trials showed that 84% of patients saw tumor shrinkage with this therapy. For patients whose disease relapses or becomes refractory, secondary therapies may be successful in providing another remission, and today’s approval will provide patients with another treatment option.”
The FDA designated zanubrutinib as a breakthrough therapy and an orphan drug. Mantle-cell lymphoma represents 3% to 10% cases of all non-Hodgkin lymphoma in the United States.
This approval was based on a phase 2 open-label, multicenter, single-arm clinical trial of 86 patients with mantle-cell lymphoma who had received at least 1 previous therapy. The overall response rate (ORR) was 84% (95% confidence interval [CI], 74-91), with a complete response rate of 59% (95% CI, 48-70) and a median duration of response of 19.5 months (95% CI, 16.6-not estimable). This approval was also based on an earlier phase 1/2 open-label, dose-escalation, multicenter, single-arm clinical trial of 32 patients with mantle-cell lymphoma who had received at least 1 previous therapy. The ORR was 84% (95% CI, 67-95), with a complete response rate of 22% (95% CI, 9-40) and a median duration of response of 18.5 months (95% CI, 12.6-not estimable).
The most common (≥20%) side effects with zanubrutinib were reduced neutrophils, decreased platelets, upper-respiratory tract infection, decreased white blood cells, decreased hemoglobin level, rash, bruising, diarrhea, and cough. The most common serious adverse reactions were pneumonia (11%) and hemorrhage (5%).
