The Effect of Adding Rituximab to CHOP-Based Therapy on Clinical Outcomes for Patients In Different Subgroups of DLBCL

Abstract 4893 The addition of rituximab to cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) has been shown to improve the outcome in all age groups with newly diagnosed diffuse large B-cell lymphoma (DLBCL). We conducted a retrospective analysis to evaluate the impact on clinical outcomes of adding rituximab to cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) treatment for diffuse large B-cell lymphoma (DLBCL) patients in china. A propensity score method was used to compensate for the non-randomized study design. From January 2004 to December 2009, 68 patients were newly diagnosed with DLBCL Using Hans' algorithm based on CD10, BCL-6, and MUM1, the non-germinal center (N-GCB) subgroup 45(66.2%) and germinal center B-cell-like (GCB) 23(33.8%). 32 in the rituximab plus CHOP-based chemotherapy (R+) group, and 36 in the CHOP-based chemotherapy only (R-) group. The complete response rate was significantly higher in the R+ group than in the R- group (81.1 vs. 68.1%, P < 0.005,); The complete response rate of N-GCB and GCB in the R+ group was78.2% and 82.1%, p>0.05 respectively. The complete response rate of N-GCB and GCB in the R- group was58.2% and 71.3 %, p P < 0.001. The rituximab can overcome poor outcomes for N-GCB subgroup of DLBCL. The progression-free survival (PFS) at 2 years was 62.4% in the R+ group and 57.0% in the R- group. The 2-year overall survival (OS) was 76.9% for the R+ group and 69.5% for the R- group, P < 0.001. The 2-year overall survival (OS) was 72% in N-GCB Subgroup and 78% in GCB Subgroup for the R+ group, and 48% in N-GCB Subgroup and 68% in GCB Subgroup for the R- group. A multivariate analysis revealed that the addition of rituximab was a strong independent prognostic factor for PFS (hazard ratio 0.64, 95% CI 0.43–0.96, P = 0.031). A subgroup analysis revealed that R+ particularly benefited N-GCB subgroup patients). IPI also showed significant impact for PFS (hazard ratio 1.72, 95% CI 1.34–2.14 for one score increase, P < 0.001 as well as OS P < 0.001. In summary, the addition of rituximab to CHOP-based chemotherapy results in better outcomes for DLBCL patients, particularly patients N-GCB subgroup of DLBCL. Disclosures: No relevant conflicts of interest to declare.