OBJECTIVES

: The aim of this study was to evaluate the cost-effectiveness of mepolizumab as an add-on alternative compared to the best available therapy (BAT). It includes a combined therapy of inhaled corticosteroid and a long acting beta agonist, plus short acting beta agonist and oral corticosteroid SOS. This analysis takes place at the public Chilean health system for the treatment of severe eosinophilic asthma.

METHODS

: A Markov model was adapted to represent the day-to-day of patients with severe asthma over a lifetime horizon. The expected direct cost measured as Chilean Pesos ($1USD= CLP$640) and utilities for the health states and exacerbation were obtained from the literature. Comparative effectiveness of mepolizumab related to exacerbation rates were estimated from clinical trials. Deterministic and Probabilistic sensitive analysis were performed to account for second order uncertainty of the model. Also, a risk subgroup analysis was conducted to evaluate the cost-effectiveness of mepolizumab across different risk population.

RESULTS

: Mepolizumab was the most effective alternative, generating 1,014 QALYs more than BAT. The incremental cost-effectiveness ratio (ICER) of mepolizumab compared to BAT was $110.273 USD per QALY gained, which is above the reference threshold for Chile ($15.618 USD). From the subgroup analysis, it was observed that the cost-effectiveness of mepolizumab increases in specific subgroups, achieving an ICER of $46.640 USD in patients with eosinophils count of 300 and more cell/mcL and an exacerbation history of at least 4 exacerbations in the past year.

CONCLUSIONS : In the light of the Chilean threshold, mepolizumab cannot be considered a cost-effective strategy. However, price discount in specific subgroups improves its cost-effectiveness profile significantly. It was estimated an ICER of $24.116 USD in the best performance subgroup with a 50% price discount.