Lifetime Cost-Utility Analyses of Deferasirox in Beta-Thalassaemia Patients with Chronic Iron Overload

Abstract

Regular blood transfusions for beta-thalassaemia patients lead to the accumulation of iron deposits in the body. In order to remove such deposits, iron chelation therapy is required. Subcutaneously administered deferoxamine has been the gold standard chelation therapy for over 40years. Deferasirox is a newer chelation therapy that is taken orally once daily. The objective of this study was to estimate the long-term costs and quality-adjusted life-years (QALYs) associated with deferoxamine and deferasirox in a cohort of transfusion-dependent beta-thalassaemia patients from a UK health service perspective. A 50-year annual cycle state transition model comprised three core health states: alive without cardiac complications, alive with cardiac complications, and dead, as well as representing other chronic complications of iron overload: diabetes, hypogonadism, hypoparathyroidism and hypothyroidism. The model was calibrated to identify sets of convergent input parameter values that predicted observed overall survival by mean lifetime compliance with chelation therapy. A pivotal non-inferiority trial informed the main estimates of the effectiveness of deferasirox, which were applied to the calibrated model. Using cost values for the year 2011, costs and utilities were summed over patients' lifetimes to estimate lifetime costs and QALY gains. Mean lifetime treatment costs for patients receiving deferoxamine were £70,000 higher than deferasirox. Drug acquisition costs were £100,000 higher for deferasirox, but administration costs associated with deferoxamine were £170,000 higher. Higher compliance associated with oral deferasirox administration led to fewer complications. Combined with the quality-of-life effects of an oral mode of administration, an average gain of 4.85QALYs for deferasirox was estimated. In the base case, deferasirox dominates deferoxamine, i.e., costs less and patients gain more QALYs. The key parameter is the proportion of deferoxamine patients using balloon infusers. Sensitivity analyses showed that even when the proportion of patients using balloon infusers is decreased from 79 to 25%, the incremental cost per QALY gained remains well under £20,000. Higher drug acquisition costs for deferasirox are offset by the avoidance of infusion-related equipment costs. Combined with health benefits derived from an oral mode of administration and improved compliance, deferasirox has a high probability of being a cost-effective intervention compared with deferoxamine.