Comparison of the Efficacy of Innovator Rituximab and its Biosimilars in Diffuse Large B Cell Lymphoma Patients: A Retrospective Analysis

Diffuse large B cell lymphoma (DLBCL) is the most common form of non-Hodgkin lymphoma among adults, although it also affects the young and the elderly. DLBCL is treated with a chimeric monoclonal antibody against CD20, a B cell surface protein, named rituximab, in combination with a multidrug chemotherapeutic regimen. However, owing to its high cost, rituximab cannot be afforded by patients in developing or underdeveloped countries. In such cases, biosimilars of rituximab have been used instead of rituximab, with equivalent efficacy. In this single center, retrospective, observational study, we have compared patient outcomes such complete response (CR), partial response (PR), and overall response rate (ORR) in a cohort of 152 patients in an Indian hospital, who were treated either with innovator rituximab or Reditux, a biosimilar. We observed that the ORRs of both groups (88% in innnovator group and 82% in biosimilar group) were comparable. There was no statistically significant difference between the two groups in terms of CR (p = 0.353), PR (p = 0.42), ORR (p = 0.23), unfavorable responses, and stable or progressive disease (p = 0.42). The number of patients who died due to complications were few, and there was no significant difference between the two groups. The differences in the 3-year event-free survival and overall survival were not statistically significant. Biosimilar rituximab can suitably and safely replace the innovator rituximab for treatment of diffuse large B cell lymphoma.