On the 14th November 2019, the U.S. Food and Drug Administration (FDA) approved zanubrutinib (BGB-3111) for the treatment of patients with relapsed/refractory (R/R) mantle cell lymphoma (MCL).1 Earlier this year, the drug received Breakthrough Therapy designation by the FDA and a Priority Review designation.
Zanubrutinib is an inhibitor of Bruton’s tyrosine kinase (BTK), a protein involved in pathways regulating B-cell proliferation, chemotaxis, and adhesion. The approval was granted based on the positive data from the multicentre phase II trial of zanubrutinib in patients with R/R MCL (NCT03206970), showing overall response rate (ORR) of 84% (95% CI: 74%, 91%), including 59% complete response (CR).2 The median duration of response (DOR) was 19.5 months and the median follow-up time was 18.4 months. The supporting phase I/II single-arm trial (NCT02343120) also showed 84% ORR, including 22% CR and 62% partial response with a median DOR of 18.5 months.1,2
The most common adverse events were decreased neutrophil and platelet count, infections of the upper respiratory tract, cough, decreased white blood cell count, decreased hemoglobulin, rash, and diarrhea.1
Clinical trials of zanubrutinib as a single agent are also ongoing in patients with untreated MCL and Waldenström macroglobulinemia. Other studies investigate the combination of zanubrutinib and obinutuzumab for treatment-naive and R/R chronic lymphocytic leukemia/small lymphocytic lymphoma, and R/R follicular lymphoma.