Treating refractory asthma with antibodies against IL-5: is it ready for prime time?

Evaluation of: Haldar P, Brightling CE, Hargadon B et al. Mepolizumab and exacerbations of refractory eosinophilic asthma. N. Engl. J. Med. 360, 973-984 (2009). Although many asthmatics have mild symptoms or are well-controlled with current anti-asthma therapies, there is a subpopulation of patients who suffer from severe asthma, characterized by persistent symptoms and frequent exacerbations, despite therapy. Such patients with refractory asthma often show eosinophilia in their sputum, which is considered a potential marker for the identification of such patients. Because eosinophils are implicated in the pathogenesis of refractory asthma, they have become a target for potential therapeutic interventions. The current prospective study evaluates the effectiveness of mepolizumab, an agent that targets IL-5, which is a mediator of eosinophilia in patients with refractory asthma and sputum eosinophilia. The study shows that this treatment reduced eosinophilia and was associated with a significant reduction in asthma exacerbations.