Efficacy and Safety of Nilotinib in CML-CP

Nilotinib is a second-generation tyrosine kinase inhibitor with improved efficacy compared to imatinib. However, there are still many patients for whom the therapeutic response is inadequate, or toxicity is limiting the treatment. Serum concentration of nilotinib was shown to affect time to response and progression in previous studies. Therefore, the investigators hypothesized that the optimal plasma level of nilotinib that is sufficient to achieve adequate clinical response while not generating major adverse events could be elucidated by the analysis of combined clinical and pharmacokinetic data. ENESTKorea is a phase 4, multi-institutional, single-arm, open-label study investigating the efficacy and safety of nilotinib at the currently approved dose (300 mg twice daily), in adult patients diagnosed as Philadelphia chromosome (Ph)-positive chronic myeloid leukemia in chronic phase (CML-CP). Plasma samples are collected every three months, for up to 12 months, to determine plasma nilotinib concentrations (PNCs). The primary endpoint is the cumulative rate of molecular response 4.5 (MR4.5; BCR-ABL1IS ≤ 0.0032%) by 24 months. Secondary endpoints include the cumulative rates of MR3 (BCR-ABLIS ≤ 0.1%) and MR4 (BCR-ABLIS ≤ 0.01%) by 12 and 24 months; time to MR3, MR4, and MR4.5; progression-free survival (PFS); overall survival (OS). Correlations between PNCs and clinical outcomes are also analyzed.