GlaxoSmithKline has reported the start of a Phase III study to evaluate the efficacy and safety of mepolizumab, an investigational interleukin-5 (IL-5) antagonist, in patients with eosinophilic granulomatosis with polyangiitis (EGPA).
The pivotal Phase III study, MEA115921, is a randomised, double-blind study with the purpose to investigate the efficacy and safety of a 300mg dose of mepolizumab (administered subcutaneously every four weeks) compared with placebo over a 52-week study treatment period in patients with relapsing or refractory EGPA receiving standard-of-care therapy including background corticosteroid therapy with or without immunosuppressive therapy.
The study is being conducted as part of an agreement between GSK and the National Institute of Allergy and Infectious Diseases. Through this collaboration the mechanisms that underlie EGPA will also be investigated, with potential future benefits for patients.
Mepolizumab is an investigational fully humanised IgG monoclonal antibody specific for IL-5 which is in development for the following diseases: EGPA, severe asthma with eosinophilic inflammation, hypereosinophilic syndrome, eosinophilic oesophagitis and nasal polyposis. The start of the Phase III programme investigating mepolizumab in patients with severe asthma with eosinophilic inflammation was announced in October 2012. Mepolizumab is not approved for use anywhere in the world.
Mepolizumab binds to human IL-5, stopping it from binding to its receptor on the surface of eosinophils. Inhibiting IL-5 binding in this manner reduces blood, tissue and sputum eosinophil levels, which in turn reduces eosinophil-mediated inflammation.