Nilotinib vs. imatinib in Japanese patients with newly diagnosed chronic myeloid leukemia in chronic phase: long-term follow-up of the Japanese subgroup of the randomized ENESTnd trial

In the ongoing, international, phase 3 study Evaluating Nilotinib Efficacy and Safety in Clinical Trials-Newly Diagnosed Patients (ENESTnd), nilotinib 300 and nilotinib 400 mg, both twice daily, are compared with imatinib 400 mg once daily for the treatment of newly diagnosed chronic myeloid leukemia in the chronic phase (CML-CP). Results for the overall population in ENESTnd (n = 846) showed that nilotinib resulted in higher response rates vs. imatinib and was well tolerated. Outcomes among Japanese patients in ENESTnd were specifically analyzed after 1 year of follow-up, and showed similar trends to the overall population; we present updated analysis of the Japanese subgroup based on 5 years of follow-up. Among Japanese patients in the nilotinib 300-mg (n = 29), nilotinib 400-mg (n = 23), and imatinib (n = 25) arms, 86.2, 78.3, and 60.0%, respectively, achieved major molecular response [BCR-ABL1 <= 0.1% on the International Scale (BCR-ABL1 (IS))] by 5 years, and 65.5, 69.6, and 40.0%, respectively, achieved MR4.5 (BCR-ABL1 (IS) <= 0.0032%). Safety results were consistent with prior reports. In this subgroup, one death occurred during treatment in the nilotinib 400-mg twice-daily arm (unknown cause), and one patient in each arm progressed to accelerated phase/blast crisis by the data cutoff.