Mepolizumab for Prednisone-Dependent Asthma with Sputum Eosinophilia

Monoclonal antibodies against interleukin-5, a potent eosinophilic cytokine and growth factor, have not shown efficacy in three clinical trials 1 – 3 in patients with asthma, despite the effectiveness of this treatment in reducing the number of eosinophils in the airway and blood. This finding has raised questions about the role of eosinophils in the pathophysiology of asthma. We reasoned that eosinophils may be in the pathobiologic chain of causation in a rare subgroup of patients with asthma who have persistent sputum eosinophilia despite treatment with oral prednisone. To test this hypothesis, we examined the prednisone-sparing effect of mepolizumab by assessing clinical . . .