Long-term outcomes of second-line versus later-line zanubrutinib treatment in patients with relapsed/refractory mantle cell lymphoma: An updated pooled analysis

Background: We previously reported results of a pooled analysis of two zanubrutinib studies in relapsed or refractory (R/R) MCL showing better survival outcomes when zanubrutinib is used in second-line versus later-line. Here, we present an updated pooled analysis with a longer follow-up of 35.2 months. Methods: Data were pooled from two studies—BGB-3111-AU-003 (NCT02343120) and BGB-3111-206 (NCT03206970) of zanubrutinib in R/R MCL. The patients were divided into two groups based on the treatment line of zanubrutinib: the second-line and the later-line group. The inverse propensity score weighting method was used to balance the baseline covariates between the groups. The primary outcome was overall survival (OS). Secondary outcomes included progression-free survival (PFS), PFS, and OS rates, objective response rate (ORR), duration of response (DOR), and safety. Results: Among 112 pooled patients, 41 (36.6%) patients received zanubrutinib as second-line and 71 (63.4%) patients as later-line therapy. After weighting, OS was significantly improved in the second-line versus later-line group (HR, 0.459 [95% CI: 0.215, 0.98]; p = 0.044) with median OS not estimable in both groups. The PFS was similar between the two groups (HR, 0.78 [95% CI: 0.443, 1.373]; p = 0.389) but with numerically longer median PFS in the second-line versus later-line group (27.8 vs. 22.1 months). ORR was numerically higher in the second-line versus later-line (88.6% vs. 85.7%), and DOR was similar between the two groups (25.2 vs. 25.1 months). Zanubrutinib showed a similar safety profile in both groups. Conclusion: Zanubrutinib in second-line treatment was associated with significantly improved OS compared with later-line treatment of R/R MCL.