Impact of Inadequate Doses of Rituximab in the Treatment of Diffuse Large B Cell Lymphoma in Malaysian Patients

Background: The current standard treatment for patients with newly diagnosed diffuse large B cell lymphoma(DLBCL) is rituximab combined with cyclophosphamide, doxorubicin, vincristine and prednisolone (CHOP).A significant number of patients were not treated with recommended dose of rituximab due to limited financialresources in Malaysia. This study evaluates the efficacy of R-CHOP like chemotherapy in Malaysian patients withDLBCL. Materials and
Methods: The study comprised a retrospective analysis of patients with DLBCL treatedat a single centre. The outcome was compared with patients who were treated with R-CHOP like and CHOP likechemotherapy. Patients who were treated with lower dose of rituximab was subanalysed for outcome.
Results:A total of 86 patients who had CHOP-like chemotherapy were included. Only 39 (45%) patients had rituximaband only 12 (29%) patients had the recommended dose. The overall response (OR) and complete response(CR) rates were 88% and 81% respectively. There was no significant difference in OR and CR in patients whohad rituximab and those without rituxmab. Those with International Prognostic Index (IPI) score of ≤2 hadsignificant higher CR rate, progression free survival (PFS) and overall survival (p<0.001).
Conclusions: The lackof significant improvement in CR and DFS in our patients may be due to an inadequate dose of rituximab.