Mepolizumab for eosinophilic severe asthma: recent studies.

INTRODUCTION: In September 2014 two large clinical studies of the anti-IL-5 monoclonal antibody mepolizumab in severe asthma were published in the New England Journal of Medicine (MENSA and SIRIUS). AREAS COVERED: Eosinophilic inflammation has long been recognised as a feature of asthma. Identification of IL-5 as a key cytokine specific for eosinophil development and survival lead to development of monoclonal antibody therapy targeting this pathway. These two important new studies suggested that this treatment could reduce exacerbation rates by 50% in asthmatic patients with persistent peripheral blood eosinophilia and persistent symptoms despite high-dose-inhaled corticosteroids and additional controller therapy, and frequent exacerbations. In the second study, mepolizumab was shown to reduce oral steroid requirement by a median of 50% in similar patients who additionally required oral prednisone to control disease. EXPERT OPINION: This represents an important new treatment option in an area of unmet need, and together with a large dose ranging study (DREAM) published in 2012 form the basis for filing for registration in the USA and Europe.