GlaxoSmithKline presents positive Phase III data for mepolizumab in severe asthma

GlaxoSmithKline announced results from two Phase III studies Wednesday demonstrating that its experimental IL-5 antagonist monoclonal antibody, mepolizumab, met the primary endpoint of reduction in the frequency of exacerbations in patients with severe eosinophilic asthma. Dave Allen, who heads the respiratory therapy area unit of GlaxoSmithKline's R&D division, said the data are "consistent with the findings from our earlier exacerbation study" and that the company "will be progressing towards global filings at the end of the year."

The first study, dubbed MEA115588, evaluated the efficacy of two dose regimens of mepolizumab in the treatment of severe eosinophilic asthma in patients who experienced frequent exacerbations despite treatment with high-dose inhaled corticosteroids plus at least one other controller medication. The 32-week trial randomised 576 patients to receive intravenous or subcutaneous mepolizumab, or placebo, every four weeks in addition to their current asthma maintenance therapy. The drugmaker observed that, compared with placebo, intravenous mepolizumab was associated with a 47-percent reduction in the frequency of clinically significant exacerbations of asthma, while subcutaneous administration was linked to a 53-percent reduction. Both results were statistically significant, the company said.

Meanwhile, the MEA115575 study assessed the ability of mepolizumab to reduce daily corticosteroid use while maintaining asthma control. The trial involved 135 patients with severe eosinophilic asthma who were on regular treatment with oral corticosteroids, high-dose inhaled corticosteroids plus an additional controller medication. Patients were randomly assigned subcutaneous mepolizumab or placebo every four weeks. Results showed that during weeks 20 to 24, patients in the mepolizumab arm achieved "greater reductions in their maintenance oral corticosteroid dose," compared with placebo, while maintaining asthma control.

Allen noted that mepolizumab is for the company "the first non-inhaled treatment for severe asthma," and that GlaxoSmithKline now has "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." GlaxoSmithKline added that it plans to present data from these studies at an upcoming scientific meeting.

Barclays analysts forecast that mepolizumab could contribute 400 million pounds ($665 million) to GlaxoSmithKline's revenue by 2021, while Deutsche Bank estimates 300 million pounds ($499 million) in sales of the drug by 2018. The compound is also being investigated as a potential treatment for chronic obstructive pulmonary disease.

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