Exenatide versus insulin glargine in patients with type 2 diabetes in the UK: a model of long-term clinical and cost outcomes

Objectives: The aim of this study was to evaluate the long-term clinical and economic outcomes associated with exenatide or insulin glargine, added to oral therapy in individuals with type 2 diabetes inadequately controlled with combination oral agents in the UK setting. Methods: A published and validated computer simulation model of diabetes was used to project long-term complications, life expectancy, quality-adjusted life expectancy and direct medical costs. Probabilities of diabetes-related complications were derived from published sources. Treatment effects and patient characteristics were extracted from a recent randomised controlled trial comparing exenatide with insulin glargine. Simulations incorporated published quality of life utilities and UK-specific costs from 2004. Pharmacy costs for exenatide were based on 20, 40, 60, 80 and 100% of the US value (as no price for the UK was available at the time of analysis). Future costs and clinical benefits were discounted at 3.5% annually. Sensitivity analyses were performed. Results: In the base-case analysis exenatide was associated with improvements in life expectancy of 0.057 years and in quality-adjusted life expectancy of 0.442 quality-adjusted life years (QALYs) versus insulin glargine. Long-term projections demonstrated that exenatide was associated with a lower cumulative incidence of most cardiovascular disease (CVD) complications and CVD-related death than insulin glargine. Using the range of cost values, evaluation results showed that exenatide is likely to fall in a range between dominant (cost and life saving) at 20% of the US price and cost-effective (with an ICER of POUNDS22 420 per QALY gained) at 100% of the US price, versus insulin glargine. Conclusions: Based on the findings of a recent clinical trial, long-term projections indicated that exenatide is likely to be associated with improvement in life expectancy and quality-adjusted life expectancy compared to insulin glargine. The results from this modelling analysis suggest that that exenatide is likely to represent good value for money by generally accepted standards in the UK setting in individuals with type 2 diabetes inadequately controlled on oral therapy.