News Feature | March 15, 2014

GSK Reports Positive Mepolizumab Phase III Study Results

By Estel Grace Masangkay

GlaxoSmithKline announced positive results from a pivotal Phase III study of Mepolizumab, its investigative IL-5 antagonist monoclonal antibody.

Dave Allen, Head of Respiratory Therapy Area Unit of the GSK R&D department, said: “We are really pleased to have generated further positive data on mepolizumab, consistent with the findings from our earlier exacerbation study. We now have two studies showing a reduction in exacerbations in a specific group of patients with a severe form of asthma who continue to exacerbate despite treatment with high doses of their current maintenance therapies.”

The drug was evaluated in the trial MEA115588 for efficacy of two dose regimens in treatment of patients with severe eosinophilic asthma. Patients stayed on their current maintenance therapy during the study and were randomized to receive either mepolizumab 75mg intravenous or 100 mg subcutaneous, or placebo every four weeks.

Both mepolizumab treatment arms met its primary endpoints and demonstrated statistically significant reductions in the frequency of clinically significant exacerbations of asthma compared to placebo. “This is very positive news for patients. For GSK it is exciting that this is the first non-inhaled treatment for severe asthma and we will be progressing towards global filings at the end of the year,” Allen said.

Asthma is a heterogeneous disease often characterized by an accumulation of eosinophils or white blood cells in the lung tissues. In general, raised eosinophils correlated with severity and frequency of exacerbations of the attacks. Interleukin-5 (IL-5) is the primary promoter of eosinophil growth, activation, and survival. The interleukin provides a crucial signal for the movement of eosinophils from the bone marrow in to the lung of patients affected with the disease.

Mepolizumab is an investigational fully humanized lgG1 monoclonal antibody developed specifically for IL-5. The antibody binds to the interleukin and inhibits it from binding to its receptor on the surface of eosinophils to reduce blood, tissue, and sputum eosinophil levels. The drug is currently in development for severe eosinophilic asthma in patients who suffer exacerbation in attacks in spite of high dose oral or inhaled corticosteroids and additional controllers such as long acting beta-2 agonist. GSK is also investigating the drug in COPD and Eosinophilic Granulomatosis with Polyangiitis (EGPA).

The company said it will present the new data at an upcoming scientific meeting as well as publish it on the GSK clinical study register and