Long-term results demonstrated that zanubrutinib remains effective with a median duration of response not reached and a largely unchanged safety profile among patients with relapsed/refractory mantle cell lymphoma (MCL), according to the results of a 3-year update from the phase 2 BGB-3111-206 registrational trial published in Blood.
Zanubrutinib is approved by the U.S. Food and Drug Administration for the treatment of patients with relapsed/refractory MCL based these phase 2 trial results. This updated analysis includes data with a median follow-up of nearly 3 years.
The single-arm, open-label, phase 2 trial (ClinicalTrials.gov Identifier: NCT03206970) treated 86 patients with relapsed/refractory MCL with zanubrutinib. The primary endpoint was overall response rate (ORR). Secondary endpoints included duration of response (DOR), time to response, progression-free survival (PFS), and safety.
The long-term analysis demonstrated an ORR of 83.7%, with 77.9% of patients having achieved complete response. The time to response was a median 2.7 months and the median DOR was not reached. The ORR was similar in the subgroup analysis, including among patients with poor prognostic markers.
The median PFS was 33.0 months, with a 36-month rate of 47.6%. However, the median PFS was not reached among patients who achieved a complete response.
The median overall survival (OS) was not reached, and the estimated 36-month OS rate was 74.8%.
The safety profile remained similar to earlier analyses, with the most common grade 3 or higher adverse events (AEs) including neutropenia and pneumonia. The incidence of infection, neutropenia, and bleeding decreased after the initial 6 months of zanubrutinib administration.
“Most AEs occurred during early-stage zanubrutinib treatment, and no new safety signals were observed after extended follow-up,” the authors wrote.
Zanubrutinib was discontinued in 9.3% of patients due to AEs.
The authors concluded that “this phase 2 study in patients with relapsed/refractory MCL with extended 35.3-month follow-up data continued to demonstrate a favorable benefit-risk profile of zanubrutinib monotherapy.”
Disclosures: This study was funded by BeiGene Ltd. and BeiGene USA, Inc. Some of the study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.
Song Y, Zhou K, Zou D, et al. Zanubrutinib in relapsed/refractory mantle cell lymphoma: long-term efficacy and safety results from a phase 2 study. Blood. 2022;139:3148-3158. doi:10.1182/blood.2021014162