Efficacy and safety of nilotinib therapy in patients with newly diagnosed chronic myeloid leukemia in the chronic phase.

ABL1-tyrosine kinase inhibitors (TKIs) have led to dramatic changes in treatment strategies for chronic myeloid leukemia in the chronic phase (CML-CP). However, clinical studies have highlighted increasing numbers of adverse events (AE) with TKIs. Although TKI modification plays a key role in AE management, this process is poorly understood, particularly in terms of the TKI nilotinib. In the present study, we retrospectively analyzed the records of 70 patients with newly diagnosed (ND)-CML-CP who were treated with nilotinib to investigate the drug potency of nilotinib and treatment management. During a median observation period of 3.4 years, 76% of patients continued nilotinib as a first-line treatment. The 1-year and overall major molecular response (MMR) rates and the overall molecular response (MR) 4.5 rate for all patients receiving first-line nilotinib therapy were 70, 84.2, and 50%, respectively. No case progressed to the accelerated or blast phase during the study. To avoid AEs during the early phase, nilotinib doses were reduced to < 600 mg/day in a third of patients (Reduced group); these patients experienced better therapeutic efficacy and a lower rate of AEs relative to those in Standard group (300 mg twice daily). Ten patients who received < 600 mg/day of nilotinib throughout the study had a 1-year MMR rate and overall MR4.5 rate of 90 and 60%, respectively. In summary, our findings indicate that careful management, including dose reduction, can yield better outcomes in patients with ND-CML-CP.