Improved survival outcomes with the addition of rituximab to initial therapy for chronic lymphocytic leukemia: a comparative effectiveness analysis in the province of British Columbia, Canada

Chemoimmunotherapy with rituximab improves survival in clinical trials in upfront chronic lymphocytic leukemia (CLL) treatment. This study compared clinical outcomes with and without rituximab added to first-line chemotherapy in a provincial cohort of CLL patients. Between 1973 and 2014, 1345 patients received CLL treatment: 48% with rituximab, 52% chemotherapy alone. Median overall survival (OS) and treatment-free survival (TFS) were significantly longer with rituximab: OS 8.9 vs. 6.2 years, p<.0001; TFS 3.6 vs. 2.1 years, p<.0001. Addition of rituximab to chemotherapy was a strong independent predictor of mortality with a 32% mortality reduction after controlling for co-variates (age, sex, stage, and treatment with purine analogs). This large population-based study complements clinical trial and registry data demonstrating the benefit of adding rituximab to first-line CLL therapy and adds further evidence of the efficacy of rituximab-based chemoimmunotherapy in a real-world setting.