OBJECTIVES: The ENESTnd study showed that in newly-diagnosed patients with Ph+ CML-CP nilotinib (300mg BID) had greater efficacy than imatinib (400mg QD) in the number of patients achieving major molecular and complete cytogenetic responses.  Fewer patients treated with nilotinib progressed to advance or blast phase than with imatinib. The objective of this analysis was to assess, from a HK societal perspective, the cost and quality-adjusted-life-years (QALYs) of imatinib versus nilotinib in newly-diagnosed Ph+ CML-CP. METHODS: A literature-based Markov model was developed to estimate the lifetime QALYs and costs of typical 47 year-old CML-CP patients initiating first-line (FL) therapy. Two periods were considered: the first year, reflecting the ENESTnd data, and all subsequent years (until all patients had died/reached 100 years), based on stratified disease progression data from the International Randomized Study of Interferon and STI571 (IRIS) study. Patients who discontinued FL therapy were modeled to receive one additional tyrosine kinase inhibitor (TKI). Prognosis after FL therapy discontinuation was modeled using published studies. Local demographics and costs were used to populate the model. Quality of life was assumed to vary by disease stage and treatment status (on/off TKI). The threshold used to define a cost-effective therapy was the WHO’s 3 x GDP/capita (i.e., HKD247,712; USD31,758; USD1 = HKD7.8). RESULTS: Compared to imatinib, nilotinib results in a gain of 2.32 life years and 2.30 QALYs. The cost/life year gain was HKD156,042 (USD20,005) and incremental cost/ QALY was HKD157,313 (USD20,168). Univariate sensitivity analysis showed results were generally robust. Key drivers were the duration of analysis, discount rates, age at therapy initiation, and inclusion/exclusion of indirect costs. In probabilistic sensitivity analysis, 95% of model replications cost ≤HKD 180,000 (USD23,077)/QALY gained.  CONCLUSIONS: Using local and non-local data, this analysis suggests that nilotinib is cost-effective compared to imatinib as FL treatment for CML-CP patients from a HK societal perspective.