Efficacy and safety of PD-1 monoclonal antibody plus rituximab in relapsed/refractory diffuse large B cell lymphoma patients.

BACKGROUND: Patients with relapsed/refractory diffuse large B-cell lymphoma (r/r DLBCL) have poor outcomes and few treatment options. We report the preliminary results of the efficacy and safety of PD-1 monoclonal antibody (mab) plus Rituximab for r/r DLBCL. METHODS: In this single-center, single-arm phase 2 and retrospective study, r/r DLBCL patients received PD-1 mab and Rituximab every 3 weeks. Immunohistochemistry, fluorescence in situ hybridization, and probe capture-based high-resolution sequencing were performed. Efficacy, safety and prognostic factors were analyzed. RESULTS: Between October 16th, 2018, and July 10th, 2022, 36 patients (10 patients in retrospective study and 26 patients in phase 2 study) were enrolled and received at least one dose of PD-1 mab combined with Rituximab. The objective response rate was 52.8%. The median progression free survival (PFS) and overall survival was 2.8 and 19.6 months, respectively. The median duration of response was 18.7 months. Rare grade 3 or 4 treatment related adverse events were observed. B2M mutations correlated with a significantly poor PFS (p = .013) and OS (p = .009) in DLBCL patients treated with this regimen. CONCLUSION: PD-1 mab combined with Rituximab could be a potential treatment option for r/r DLBCL with manageable safety profile.