Background: Chronic lymphocytic leukemia (CLL) is characterized by accumulation of B cells in blood, lymphoid tissues and bone marrow. Addition of rituximab to CLL chemotherapy regimens has been associated with improved survival. The aim of this study was to establish efficacy and safety of Zytux™ in comparison to MabThera® in treatment of CLL.
Materials and methods: Seventy CLL patients who met the criteria for entering the study were randomized into two groups (35 patients in each group). Both groups received Fludarabine and Cyclophosphamide plus Rituximab as part of the FCR regimen. Group A was treated with Zytux™, and group B was treated with MabThera®. A non-inferiority margin of 20% for the primary outcome was defined to examine the similarity between Zytux™ and MabThera®.
Results: Baseline demographic characteristics showed no statistically significant difference between the two groups. The two treatment groups were comparable in terms of laboratory and clinical findings, cellular index changes and CD (5, 19, 20 and 23) counts during therapy cycles and at the end of the treatment period. Regarding safety results, Zytux™ demonstrated a similar profile of adverse reactions in comparison to MabThera®. Moreover, the overall response rate was 88% and 89% for Zytux™ and MabThera®, respectively (CI -0.17, 0.18).
Conclusion: Results showed non-inferiority of Zytux™ in terms of efficacy and adverse events as a biosimilar version of MabThera®.
Keywords: Chronic lymphocytic leukemia; Clinical trial; Mabthera®; Rituximab; Zytux™.