Efficacy and Safety of Zanubrutinib-Containing Regimens in Patients with Secondary CNS Relapse in Diffuse Large B-Cell Lymphoma

Background: In the era of immune-targeted therapy represented by rituximab, despite improved remission and survival rates in patients with diffuse large B-cell lymphoma (DLBCL), central nervous system (CNS) relapse, occurring in some DLBCL patients after achieving remission, remains a clinical challenge. Zanubrutinib is one of a new generation of BTK inhibitors that have higher blood-brain barrier permeability compared to other BTK inhibitors.

Research Design and Methods: We performed a multicenter retrospective study to evaluate the efficacy and safety of Zanubrutinib-containing regimens for salvage treatment in 28 relapsed DLBCL patients with CNS involvement treated in 6 centers from January 2020 to December 2021.

Results: The IPI score and CNS-IPI score did not have good enough predictive significance for lack of consistency of the median time from the initial diagnosis to CNS recurrence. Of the 28 patients, 16 had targeted next-generation sequencing (NGS) data. NGS test was performed on their tissue samples that were obtained at initial diagnosis and/or at the timepoint of CNS relapse in DLBCL. 8 at the time of initial diagnosis and 10 at the time of recurrence, with 2 of them having undergone NGS sequencing at both initial diagnosis and recurrence. Median study follow-up from CNS relapse was 8.55 months, all patients were evaluated for response with 20/28 (71.4 %) showing a response: 11 CR, 9 PR, and 4 SD, 4 PD. The median PFS is 6.6 months, and the median OS has not yet been reached. Notably, MYD88, CD79B, or TP53 mutations tested at diagnosis in these patients were associated with significantly more favorable treatment response, while patients with a dual rearrangement of MYC and BCL2 and/or BCL6 genes did not get a treatment response to Zanubrutinib-containing regimens. It has well-tolerated toxicity with few adverse events requiring treatment discontinuation or dose reduction.

Conclusion: Zanubrutinib-containing regimens extended PFS and OS in relapsed DLBCL patients with CNS involvement.