Real-life comparison of nilotinib versus dasatinib as second-line therapy in chronic phase chronic myeloid leukemia patients

Tyrosine kinase inhibitors (TKIs), the backbone of treatment for chronic phase chronic myeloid leukemia patients (CP-CML), have changed the long-term outcome of the disease. Nonetheless, over 20\% of patients fail front-line therapy due to intolerance or resistance. A head-to-head comparison of dasatinib and nilotinib as second-line treatment outside of sponsored clinical trials has not been reported. We retrospectively analyzed 131 CP-CML patients who, after front-line imatinib failure, switched to a second-line therapy with nilotinib (59, 45\%) or dasatinib (72, 55\%). Median duration of second-line treatment was 33 months (range 2-100). The reason for switching therapy was resistance in 83.2\% and intolerance in 16.8\% of patients. The overall survival of the entire cohort at 7 years was 78.9\%, while it was 72\% and 85.6\% for patients treated with dasatinib and nilotinib, respectively (p=0.287). With regard to efficacy after 12 months of treatment, 108 patients were evaluable for molecular response: 47\% achieved a major molecular response and 18.2\% a deep molecular response with dasatinib, compared to 38\% and 16.2\% with nilotinib (p=ns). We observed 35\% of grade 3-4 adverse events, more frequently in the dasatinib group (47\%) compared to the nilotinib group (22\%), without affecting molecular responses. Our study suggests that, in the real-life setting, dasatinib and nilotinib used as second-line treatment in CP-CML are equally effective, with high molecular response rates and an acceptable tolerability.