Mepolizumab: A reassessment of clinical benefits in eosinophilic granulomatosis with polyangiitis (Churg–Strauss)

Published online: December 19, 2018

Eosinophilic granulomatosis with polyangiitis (EGPA) (Churg–Strauss) is a rare disease in which patients experience asthma, inflammation of blood vessel walls (vasculitis), and increased numbers of eosinophils (a type of white blood cell) in the blood and tissue. EGPA is mainly treated with glucocorticoids (also known as “steroids”), such as prednisone or prednisolone. Even with treatment, symptoms often recur and high doses of glucocorticoids are required. However, regular use of glucocorticoids is associated with serious and sometimes irreversible side effects. Mepolizumab is an injectable therapy that reduces the number of eosinophils in the blood.

In a recent 52-week clinical trial of 136 patients with EGPA, 53% of patients treated with mepolizumab and standard medications achieved remission compared with 19% of patients treated with placebo and standard medications. Remission was defined as having no evidence of vasculitis while on a daily glucocorticoid (prednisone or prednisolone) dose of 4 mg or less. However, there are several ways other than remission to define treatment benefit in patients with EGPA. In this article in The Journal of Allergy and Clinical Immunology (JACI), Steinfeld and colleagues used the range of data obtained during the clinical trial to assess post hoc (after the initial trial was analyzed) the different ways that patients with EGPA may benefit from treatment with mepolizumab. The investigators assessed whether or not patients experienced clinical benefit based on any of three outcomes: 1) remission, 2) a reduction in glucocorticoid dose, or 3) being relapse free during the study.

The authors found that significantly more patients treated with mepolizumab (78%–87%) compared with placebo (32%–53%) experienced clinical benefit by achieving remission, having a greater likelihood of being able to reduce their daily glucocorticoid dose, or being relapse free. These responses to mepolizumab treatment are meaningful and highlight that, in diseases such as EGPA that have complex symptoms, clinical benefit may be best assessed using several features of treatment response, rather than using a single feature.

The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.

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