Mepolizumab for the treatment of severe eosinophilic asthma

Published data on the pharmacology, pharmacokinetics and pharmacodynamics, and clinical efficacy and safety of the interleukin-5 antagonist mepolizumab are reviewed.

Asthma of the eosinophilic phenotype is characterized by persistent eosinophilic airway inflammation promoted primarily by T-helper type 2 cytokines, the key regulator of eosinophils. Patients with severe eosinophilic asthma are burdened by the need to administer high doses of corticosteroids to help manage their symptoms. In November 2015, mepolizumab (Nucala, GlaxoSmithKline) gained U.S. marketing approval for use as an add-on maintenance treatment for severe eosinophilic asthma in patients 12 years of age or older, making it the first personalized targeted therapy for this population. Efficacy results from clinical trials provided evidence of the corticosteroid-sparing effects of mepolizumab and its ability to reduce both blood and sputum eosinophil counts. Safety data from several Phase II or III studies involving a total of more than 1,300 patients indicated that mepolizumab was generally well tolerated, and types and rates of adverse events in mepolizumab recipients were comparable to those reported with placebo use; the only mepolizumab-associated serious adverse drug events were asthma exacerbations in 2 patients. The recommended dosage of mepolizumab is 100 mg administrated via subcutaneous injection every 4 weeks.

Mepolizumab is a safe and efficacious novel add-on therapy for a small subgroup of patients with severe eosinophilic asthma whose asthma is not adequately controlled by standard regimens for asthma treatment.