The first non-inhaled treatment for a difficult-to-treat form of severe asthma is getting closer to market after GlaxoSmithKline said it would initiate global filings for the drug at the end of this year, on the back of strong late-stage clinical data.

Mepolizumab - a monoclonal antibody that inhibits interleukin 5 - is being investigated as a treatment for severe eosinophilic asthma in patients who experience exacerbations despite high-dose oral or inhaled corticosteroids (ICS) and an additional controller such as long-acting beta-2 agonist.

Two Phase III clinical trials, findings of which were released this week, have shown that patients taking the drug were able to achieve greater reductions exacerbations and in the dose of maintenance oral corticosteroids versus those on placebo, while maintaining asthma control.

In study MEA115588, mepolizumab 75mg cut the frequency of clinically significant exacerbations of asthma by 47% versus placebo, while the 100mg dose cut the amount by 53%.

The findings, says Dave Allen, Head, GSK Respiratory Therapy Area Unit, are "very positive news for patients".

Despite advances in asthma therapy, there is still a small group of patients with severe asthma who suffer frequent exacerbations and often have a poor quality of life, and currently their treatment options are limited. 

If approved, mepolizumab is unlikely to generate huge amounts of money for GSK, as the its target population is only about 4% of asthma patients. Nevertheless, the product will lend further weight to the drug giant's growing lung disease portfolio. 

Mepolizumab is also being investigated in COPD and Eosinophilic Granulomatosis with Polyangiitis (EGPA).