Long-term outcome of a phase 2 trial with nilotinib 400 mg twice daily in first-line treatment of chronic myeloid leukemia

Nilotinib is a second-generation tyrosine kinase inhibitors that has been approved for the first-line treatment of chronic phase chronic myeloid leukemia, based on the results of a prospective randomized study of nilotinib vs. imatinib (ENESTnd). Apart from this registration study, very few data are currently available on nilotinib first-line. We report here the long-term, 6-year, results of the first investigator-sponsored, GIMEMA multicenter phase II, single-arm, trial with nilotinib 400 mg twice daily as first-line treatment in 73 chronic-phase chronic myeloid leukemia patients. Six-year overall survival and progression-free survival were 96%, with one death after progression to blast phase. At 6 years, 75% of the patients were still on nilotinib. The cumulative incidence of major molecular response was 98%; only one patient had a confirmed loss of major molecular response. The cumulative incidence of deep molecular response (MR 4.0) was 76%. Deep molecular response was stable (≥ 2 years) in 34% of these patients. Cardiovascular adverse events, mainly due to arterial thrombosis, occurred in 11/73 patients (15%), after 24 to 76 months of therapy. They were more frequent in elderly patients, and in those with baseline cardiovascular risk factors. None was fatal, although there was a relevant morbidity. This is the study with the longest follow-up of a high dose nilotinib (400 mg twice daily), highlighting the high efficacy and the cardiovascular toxicity of the drug (CTG.NCT.00481052).