Economic Evaluation of Umeclidinium/Vilanterol versus Umeclidinium or Salmeterol in Symptomatic Non-Exacerbating Patients with COPD from a UK Perspective Using the GALAXY Model.

Introduction: Dual bronchodilators are recommended as maintenance treatment for patients with symptomatic COPD in the UK; further evidence is needed to evaluate cost-effectiveness versus monotherapy. Cost-effectiveness of umeclidinium/vilanterol versus umeclidinium and salmeterol from a UK healthcare perspective in patients without exacerbations in the previous year was assessed using post hoc EMAX trial data. Methods: The validated GALAXY model was populated with baseline characteristics and treatment effects from the non-exacerbating subgroup of the symptomatic EMAX population (COPD assessment test score ≥10) and 2020 UK healthcare and drug costs. Outputs included estimated exacerbation rates, costs, life-years (LYs), and quality-adjusted LYs (QALYs); incremental cost-effectiveness ratio (ICER) was calculated as incremental cost/QALY gained. The base case (probabilistic model) used a 10-year time horizon, assumed no treatment discontinuation, and discounted future costs and QALYs by 3.5% annually. Sensitivity and scenario analyses assessed robustness of model results. Results: Umeclidinium/vilanterol treatment was dominant versus umeclidinium and salmeterol, providing an additional 0.090 LYs (95% range: 0.035, 0.158) and 0.055 QALYs (-0.059, 0.168) with total cost savings of £690 (£231, £1306) versus umeclidinium, and 0.174 LYs (0.076, 0.286) and 0.204 QALYs (0.079, 0.326) with savings of £1336 (£1006, £2032) versus salmeterol. In scenario and sensitivity analyses, umeclidinium/vilanterol was dominant versus umeclidinium except over a 5-year time horizon (more QALYs at higher total cost; ICER=£4/QALY gained) and at the lowest estimate of the St George's Respiratory Questionnaire treatment effect (fewer QALYs at lower total cost; ICER=£12,284/QALY gained); umeclidinium/vilanterol was consistently dominant versus salmeterol. At willingness-to-pay threshold of £20,000/QALY, probability that umeclidinium/vilanterol was cost-effective in this non-exacerbating subgroup was 95% versus umeclidinium and 100% versus salmeterol. Conclusion: Based on model predictions from a UK perspective, symptomatic patients with COPD and no exacerbations in the prior year receiving umeclidinium/vilanterol are expected to have better outcomes at lower costs versus umeclidinium and salmeterol