Economic evaluation and budgetary burden of mepolizumab in severe refractory eosinophilic asthma

Mepolizumab is indicated as an additional treatment of severe refractory eosinophilic asthma. The observed differences in  population subgroups according to plasma eosinophil count, the  existence of patients with high levels of immunoglobulin E who are  candidates of omalizumab and mepolizumab, as well as mepolizumab's  economic impact, lead to make efficient economic studies for clinical  decision making. The aim was to analyze mepolizumab's cost-efficacy  and budget impact.

Cost comparison and the use of mepolizumab's budgetary  impact was performed, from the Spanish National Health System's  perspective. Among the assessed alternatives, inhaled systemic  corticosteroids, plus long acting beta agonist (β2) and/or oral systemic  corticosteroids in patients with non immunoglobulin E-mediated severe  allergic asthma, and said treatment along with omalizumab in patients  with immunoglobulin E mediated eosinophilic allergic asthma were  included. Its efficacy was evaluated through avoided clinically relevant  exacerbations. The direct costs associated with exacerbation were  assessed.

Mepolizumab's long run average incremental cost regarding omalizumab's is 797 euros per patient a year. Considering  omalizumab's alternative discounted price, including mepolizumab for  patients with immunoglobulin E mediated eosinophilic allergic asthma  would increase public spending from 2.3 to 4.6 million euros. Given  omalizumab's notified price, the gradual introduction of mepolizumab in  the Spanish National Health System would save 3.6 million euros in  three years. For non immunoglobulin E-mediated severe asthma  patients, the avoided cost/exacerbation by introducing mepolizumab is  15,085 euros, assuming a gradual market penetration of mepolizumab. In patients with ≥ 500 eosinophils/μL, this cost decreases to 7,767  euros per avoided exacerbation with a budgetary impact of 183.2 million  euros in three years with a progressive penetration of mepolizumab.

The cost comparison between mepolizumab and  omalizumab in immunoglobulin E mediated eosinophilic asthma patients  suggests a use of the lower cost drug, promoting price competition.  Additionally, prioritizing its use among non immunoglobulin E-mediated  severe refractory eosinophilic asthma patients and ≥ 500 eosinophils/μL  plasma level patients, would improve its efficiency as well as  reducing its budgetary impact.