GlaxoSmithKline's mepolizumab is now ready for late-stage testing after turning in a strong performance in Phase II trials assessing the experimental drug in a rare and hard-to-treat form of asthma.

The Phase IIb trial was designed to investigate whether mepolizumab - a monoclonal antibody that inhibits interleukin 5 - can safely reduce the risk of asthma exacerbations associated with eosinophilic airway inflammation.

In the trial, which was published in The Lancet, 621 patients were randomised to receive one of three different intravenous doses of GSK's drug or a placebo.

Results showed that the highest dose of mepolizumab (750mg) induced a 52% reduction in clinically significant asthma exacerbations compared to the control arm.

Interestingly, the lowest dose of the drug (75mg) was associated with a 48% reduction in exacerbations, while patients taking the mid-dose (250mg) experienced 39% less than those given a placebo.

The findings suggest that mepolizumab "seems to be a safe and effective treatment option for patients with eosinophilic asthma that is associated with frequent flare-ups, and may reduce the need for conventional treatment with oral corticosteroids that can have serious side effects including osteoporosis, high blood pressure and impaired growth in children," said study investigator Ian Pavord, Britain's University Hospitals of Leicester National Health Service Trust.

Phase III by year-end

While findings are still being analysed, the company is hoping to get mepolizumab into Phase III clinical trials by the end of the year, a GSK spokeswoman confirmed to PharmaTimes World News.

If approved, it is not likely to rake in huge amounts of money, as the target population for the drug is only about 4% of asthma patients. Nevertheless, the product will add further ballast to the drug giant's growing lung disease portfolio. 

"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.  Currently these patients have limited treatment options.  Results from the DREAM study have shown that mepolizumab has the potential to become an important future treatment option for these patients," GSK said in an emailed statement. 

In 2009, GSK pulled back an application to market mepolizumab in Europe for hypereosinophilic syndrome, after regulators said they needed more clinical data to determine its clinical benefit in this setting, and the firm is also studying the drug's potential in Churg-Strauss syndrome in Phase II trials, the spokeswoman said.