Rituximab Treatment Strategy for Patients with Diffuse Large B-Cell Lymphoma after First-Line Therapy: A Systematic Review and Meta-Analysis

BACKGROUND: Rituximab in combination with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) significantly prolonged event-free survival in first-line chemotherapy for patients with diffuse large B-cell lymphoma (DLBCL). But relapse and refractory DLBCL occur frequently. Although rituximab is effective, its role in salvage therapy after autologous transplant remains unclear. Maintenance therapy with rituximab in responding patients after first line chemotherapy may be a useful novel approach capable of eradicating minimal residual disease and to bring survival benefit. This systematic review and meta-analysis evaluated the effects of rituximab maintenance treatment and salvage therapy of patients with DLBCL. METHODS: We performed a systematic review and meta-analysis of randomized controlled trials and compared rituximab maintenance or salvage therapy at relapse with observation. We searched the Coehrane Library, PubMed, EMBASE, conference proceedings, databases of ongoing trials, and references of published trials. Two reviewers independently assessed the quality of the trials and extracted data. Hazard ratios for time-to-event data were estimated and pooled. RESULTS: Seven trials including 1470 DLBCL patients were included in this systematic review and meta-analysis. Patients treated with maintenance rituximab have better overall survival (OS) and event-free survival (EFS) than patients in the observation arm, but there was no statistical significance. Patients who received rituximab salvage therapy for relapse or refractory DLBCL have statistically significantly better OS [HR of death = 0.72, 95% CI (0.55-0.94), P = 0.02], progression-free survival (PFS) [HR = 0.61, 95% CI (0.52-0.72), P < 0.05], odds ratio (OR) [RR = 1.26, 95% CI (1.07-1.47), P = 0.004] than patients in the observation arm. The rate of infection-related adverse events was higher with rituximab treatment [RR = 1.37, 95% CI = (1.14 - 1.65) P=0.001]. CONCLUSIONS: After first-line chemotherapy, the two rituximab-combined treatment strategies, including maintenance and salvage therapies can bring survival benefit. But due to the few studies, the low methodological quality assessment and the low outcome evidence quality, it's not confirmed that the two strategies are better than normal chemotherapy regimens. More high-quality randomized controlled trials are still needed to provide reliable evidence. The higher rate of infections after rituximab therapy should be taken into consideration when making treatment decisions.