Positive results in a second phase III trial of severe asthma therapy mepolizumab puts GlaxoSmithKline on track to file for regulatory approval around the end of this year.
Mepolizumab is an interleukin-5 antagonist and is being developed to treat severe eosinophilic asthma, a form of the disease that is particularly virulent and often resists treatment even with high-dose inhaled steroids and bronchodilators. Up to a third of all asthma patients are thought to have the eosinophilic form of the disease.
GSK’s drug met its objective of reducing the frequency of asthma exacerbations in the 32-week trial, which compared two doses of the antibody – given monthly (either subcutaneously or intravenously) on top of patients’ usual asthma therapy – to placebo. Both doses were significantly more effective than placebo but did not appear to be associated with any serious side effects.
“This is very positive news for patients,” commented Dave Allen, who heads GSK’s respiratory R&D group. “For GSK it is exciting that this is the first non-inhaled treatment for severe asthma.”
If approved, mepolizumab would become the second biologic therapy for asthma after Novartis’ immunoglobulin E (IgE) inhibitor Xolair (omalizumab), which brought in sales of $613m as an allergic asthma therapy last year and was also recently approved for severe hives.
Mepolizumab is also vying with other new drug candidates in late-stage trials for severe asthma, notably AstraZeneca’s benralizumab and Teva’s Cinquil (reslizumab), both IL-5 inhibitors, as well as Regeneron/Sanofi’s IL-4 and IL-13 blocker dupilumab. Analysts at Cazenove have previously predicted modest sales for mepolizumab of around £200m ($332m) at peak.
GSK originally developed mepolizumab as a treatment for a rare and sometimes fatal condition called hypereosinophilic syndrome (HES), but withdrew its marketing application for this indication in 2009 in EU after a regulatory request for additional data on its clinical benefits.
The antibody is being investigated in chronic obstructive pulmonary disease (COPD) and a form of vasculitis known as eosinophilic granulomatosis with polyangiitis (formerly known as Churg-Strauss syndrome).