P15 Cost effectiveness of mepolizumab for severe eosinophilic asthma from the uk perspective

Introduction Severe asthma patients have limited therapeutic options. These patients remain at risk of exacerbations, their quality of life is negatively impacted and they place a significant burden on the health service. Mepolizumab is licensed for use in patients with severe eosinophilic asthma. As reimbursement authorities expect evidence of health economic benefits, this study aimed to estimate the cost-utility of mepolizumab as an add-on therapy to standard of care (SOC) versus SOC alone. Methods A de novo Markov cost-utility model was produced which compared the costs and outcomes of mepolizumab vs. SOC over a lifetime horizon. Primary analysis was based on data from the MENSA clinical trial (NCT01691521). Patients entering the model were assigned to mepolizumab or SOC and experienced treatment-specific probabilities of exacerbation events with an associated risk of mortality and disutility. The model included a continuation criteria where patients on mepolizumab who failed to demonstrate an exacerbation reduction were transitioned to the SOC arm. Costs and health outcomes were discounted annually at 3.5%. The model did not account for indirect costs or value in steroid reduction. Results In the basecase analysis (patients with ≥300 eosinophil cells/µL and ≥4 exacerbations in the previous 12 months) the incremental cost-effectiveness ratio (ICER) of add-on mepolizumab compared with SOC was £30,268/QALY gained. Scenario analyses showed that the ICER was sensitive to the starting age of the cohort, the source of utility and asthma-related mortality. Conclusion Mepolizumab represents a clinically efficacious and cost-effective alternative to SOC.