The FDA granted accelerated approval to zanubrutinib for use by adults with previously treated mantle cell lymphoma.
Zanubrutinib (Brukinsa, BeiGene) — an oral Bruton tyrosine kinase (BTK) inhibitor — previously received breakthrough therapy designation for this indication.
“Today’s FDA approval of Brukinsa ... validates it as an important treatment option for people with relapsed or refractory mantle cell lymphoma,” John V. Oyler, chairman, co-founder and CEO of BeiGene, said in a company-issued press release. “We hope this is the first of many approvals for Brukinsa as we continue to evaluate its potential in other hematologic cancers.”
The FDA based the approval on efficacy results from two single-arm clinical trials in which a combined 118 patients with relapsed or refractory mantle cell lymphoma received zanubrutinib. Investigator-assessed overall response rate served as the primary endpoint in both trials.
Results of a multicenter phase 2 trial showed an ORR of 84% (95% CI, 74-91), including a 59% complete response rate and 24% partial response rate. Median duration of response was 19.5 months (95% CI, 16.6-not estimable).
Results of a global phase 1/phase 2 trial showed an ORR of 84% (95% CI, 67-95), including a 22% complete response rate and 62% partial response rate. Median duration of response was 18.5 months.
“BTK inhibition is an established mode of treatment for patients with mantle cell lymphoma, but many patients treated with previously approved BTK inhibitors do not fully respond to BTK therapy or are forced to discontinue treatment early due to side effects,” Luhua “Michael” Wang, MD, professor in the department of lymphoma and myeloma at The University of Texas MD Anderson Cancer Center, said in the release. “We have a new option for our adult patients who have received one prior systemic or targeted therapy and are living with mantle cell lymphoma, an aggressive blood cancer that’s often diagnosed at a more advanced stage.”
The most common adverse reactions among zanubrutinib-treated patients included decreased neutrophil count, decreased platelet count, upper respiratory tract infection, decreased white blood cell count, decreased hemoglobin, rash, bruising, diarrhea, cough, musculoskeletal pain, pneumonia, urinary tract infection, hematuria, fatigue, constipation and hemorrhage. The most frequent serious adverse reactions were pneumonia (11%) and hemorrhage (5%).
Eight patients (7%) discontinued treatment due to adverse reactions. The most frequent adverse reaction that led to treatment discontinuation was pneumonia (3.4%). One (0.8%) patient experienced an adverse event that led to dose reduction.