An Economic Evaluation of Dasatinib for the Treatment of Imatinib-Resistant Patients with Chronic Myelogenous Leukaemia.
Authors: Taylor Matthew J , Saxby Ruth C , Davis Catherine 
Published: October 2019

Abstract
Abstract 4535

BACKGROUND & AIMS
Chronic myelogenous leukaemia (CML) is a progressive disease that is associated with significant health and economic burden. Whilst the short-term response to current treatments such as imatinib is relatively high, durable response is difficult to achieve in patients with resistant disease. This study estimates the lifetime costs and health outcomes associated with the use of dasatinib in the treatment of imatinib-resistant CML patients.

METHODS
A Markov model was developed to estimate the lifetime costs and health outcomes associated with current treatments for CML in the chronic phase of the disease who are resistant to imatinib 400 mg daily. Three treatment options were modelled: (i) dasatinib 100mg, (ii) imatinib 800mg and (ii) nilotinib 800mg. Patients progressed through the stages of the disease at different rates, based on their initial best response to treatment (drawn from existing clinical trials). Unit costs were drawn from national databases, and were multiplied by resource use to estimate total costs. Resource use was dependent upon the patient's current health state and response level. Health benefits were measured using quality-adjusted life years (QALYs). Quality of life was based on the patient's current health status and level of response; utility values were obtained through a survey. Results were discounted at 3.5% p.a and probabilistic sensitivity analysis was undertaken to estimate the level of confidence around the results of the models.

RESULTS
This analysis shows that for imatinib-resistant patients starting treatment in the chronic phase, dasatinib treatment is both more effective and less costly than treatment with high-dose imatinib; it is the dominant treatment in terms of cost-effectiveness. Specifically, over a patient's lifetime, dasatinib treatment is associated with an average of 5.70 (discounted) QALYs, compared to 5.56 with imatinib. During that same period, dasatinib treatment would be expected to cost £260,866, compared with £311,685 for imatinib. The avoided costs result from reduced hospital admissions and other healthcare resource in patients treated with dasatinib. When compared against nilotinib, dasatinib produced an additional 0.30 QALYs, and incurred a total increase in costs of £2,546. The incremental cost-effectiveness ratio was, therefore, £8,554 per QALY.

CONCLUSIONS
This analysis has demonstrated that dasatinib is more effective than both imatinib and nilotinib in the treatment of imatinib-resistant patients with chronic-phase CML. The analysis estimates dasatinib treatment to be less costly than imatinib in the long term; therefore, dasatinib is a cost-effective option in the treatment of CML. Whilst dasatinib treatment results in slightly increased costs than nilotinib, due to predicted increased life expectancy, it remains a cost-effective treatment.

Disclosures:
Taylor: York Health Economics Consortium: Consultancy, Research Funding. Saxby:York Health Economics Consortium: Consultancy, Research Funding. Davis:Bristol-Myers Squibb: Employment.