Front-line fludarabine-cyclophosphamide-rituximab (FCR) in 110 patients with chronic lymphocytic leukaemia (CLL): real-life experience with long-term outcomes, toxicities and responses to second-line therapies

Fludarabine-cyclophosphamide-rituximab (FCR) has been the gold standard front-line treatment for fit CLL patients until novel agent's introduction. Decision between either time-limited FCR or "endless" Bruton's tyrosine kinase inhibitor (BTKi) therapy may be difficult in fit IGHV-mutated-non-TP53 cases. We describe the outcomes after front-line FCR in 110 CLL patients from 5 centres in Catalonia, Spain, over a period of more than 10 years. ORR was 96.3% and CR 74.5%. Median second-treatment free survival (TFS1) was 6.2 years and median OS was 10.8 years. 50 (45.5%) patients required a subsequent therapy. Median third-treatment free survival was better for BTKi than for chemotherapy ± antiCD20 strategies (not reached vs 3.1 years, p = 0.003). Only 50 (45.5%) patients completed 6 cycles of FCR, and the main reason for discontinuation was cytopenia 29 (26.4%). 15 (13.6%) patients developed a second cancer, and 5 (4.5%) patients experienced a Richter's transformation (RT). At the end of follow-up, 50 (45.5%) patients remained in CR. Response rates, TFS1, OS, RT, and second cancers did not differ between patients treated with 6 vs 4 cycles of FCR. In conclusion, front-line FCR treatment leads to very long CR in almost half of patients, and BTKi yields excellent outcomes in relapsed patients.