Recent studies have concluded that mepolizumab may improve exacerbations in patients with severe eosinophilic asthma, an adult-onset asthma which represents less than 5% of all asthma.
IL-5 is a chemical messenger in the immune system that stimulates the growth of eosinophils. In eosinophilic asthma, eosinophils are present in the lungs. When mepolizumab was given to people with eosinophilic asthma, it eliminated eosinophils from the bloodstream,and reduced eosinophils in the lungs and bone marrow. Mepolizumab also reduced the number of asthma exacerbations, and reduced the need for corticosteroids. Mepolizumab improved the quality of life, but the improvement was "not clinically meaningful," according to a reviewer.
In a recent multi-centre, double-blinded, randomised, controlled trial study of Mepolizumab in severe eosinophilic asthma, Mepolizumab reduced the number of clinically significant exacerbations compared to a placebo. Additionally Mepolizumab reduced sputum and blood eosinophil counts and was shown to be safe for up to 12 months.
Mepolizumab is also in development for the management of hypereosinophilic syndrome by GlaxoSmithKline (GSK) and has received orphan drug designation by the FDA. Mepolizumab has been shown to reduce the need for corticosteroids and improve symptoms in FIP1L1/PDGFRA negative hypereosinophilic syndrome.