Dexpramipexole: A new antieosinophil drug?

Abstract

In this issue of Blood, Panch et al report that dexpramipexole reduces blood and tissue eosinophils and enables glucocorticoid reduction or cessation in patients with the hypereosinophilic syndromes (HESs).1 Four of the 10 treated patients met the primary end point. The figure shows findings in 3 responders, patients 5, 7, and 15, who had complete and sustained reductions in AECs. They discontinued glucocorticoids, and all were asymptomatic with AEC 0/mL beginning at about 2 months and persisting to a median of 29 months’ treatment. In patient 5, pre- and posttreatment biopsies of the esophagus and duodenum showed an absence of eosinophil infiltration at week 24. Adverse reactions did not lead to drug discontinuation. These results suggest that dexpramipexole is an effective treatment of some HES patients; however, only 3 of the 10 were impressive responders.