Addition of rituximab to CEAC conditioning for autologous hematopoietic stem cell transplantation provides no survival benefit in diffuse large B-Cell lymphoma: A propensity score-matched cohort study

High dose chemotherapy followed by autologous hematopoietic stem cell transplantation (ASCT) is the standard of care for relapsed or refractory diffuse large B-cell lymphoma (DLBCL). Rituximab has significantly improved outcomes of DLBCL patients when incorporated into first-line or second-line chemotherapy. However, whether its addition to conditioning regimens further improves efficacy remains controversial. In this study, we explored the efficacy and safety of Rituximab with CEAC conditioning, a regimen previously reported by our center. We compared the CEAC regimen with or without Rituximab in 80 DLBCL patients with propensity score matching method at a ratio of 1:1 (40 CEAC, 40 R-CEAC). The objective response rate (ORR) was 95% in the CEAC cohort compared to 93% in the R-CEAC cohort (P = 0.615). The complete response (CR) rate was 70% versus 60%, respectively (P = 0.348). The 3-year progression-free survival (PFS) of the CEAC cohort and the R-CEAC cohort were 73% (95% CI 61%-89%) versus 61% (95% CI 47%-79%) (HR 1.706, 95%CI 0.774–3.763, P = 0.178). The 3-year overall survival (OS) of the CEAC cohort and the R-CEAC cohort were both 79% (95% CI 67%-93%) (HR 1.083, 95%CI 0.418–2.808, P = 0.869). And 3-year cumulative incidence of relapse (CIR) was 21% (95% CI 6.8%-33%) and 38% (95% CI 18%-50%) (HR 1.842, 95%CI 0.779–4.339, P = 0.162) in the CEAC cohort and the R-CEAC cohort. For the safety profile, no difference was observed in adverse events. In conclusion, the addition of rituximab to the CEAC conditioning regimen did not improve survival outcomes and is not recommended for DLBCL patients undergoing ASCT.