R-CHOP compared to R-CHOP + X for newly diagnosed diffuse large B-cell lymphoma: a systematic review and meta-analysis

Background: Treatment with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) is standard of care first line treatment for diffuse large B-cell lymphoma (DLBCL), though outcomes remain suboptimal. Methods: We performed a systemic review and meta-analysis of randomized controlled trials comparing the efficacy and safety of R-CHOP vs. R-CHOP + X (addition of another drug to R-CHOP) as first line treatment for DLBCL. We searched Cochrane Library, PubMed and conference proceedings up to September 2020. Results: Our search yielded ten trials including 4206 patients. The added drug was bortezomib or lenalidomide in three trials each, and gemcitabine, bevacizumab and ibrutinib, each drug in one trial. R-CHOP + X was associated with statistically significant improved disease control (HR 0.88, 95% CI 0.78–0.99). The point estimate was in favor of improved overall survival with R-CHOP + X (hazard ratio (HR) 0.87, 95% confidence interval (CI) 0.75–1.00), although this was not statistically significant. Subgroup analysis revealed improved disease control with the addition of lenalidomide and in patients younger than 60 years. R-CHOP + X was associated with an increase in serious adverse events and grade III/IV hematologic toxicity. Conclusion: The addition of another drug to frontline R-CHOP treatment for DLBCL did not result in a significant improvement in OS, although we did observe improved disease control compared to R-CHOP, perhaps most evident with the addition of lenalidomide. Yet, RCHOP + X was associated with an increased risk for serious and hematological adverse events. Further studies could reveal subgroups that would benefit most from augmentation of standard R-CHOP.