A drug approved to treat a severe form of asthma has accelerated the health of people with rare chronic immune disorders called hypereosinophilic syndromes (HES) for whom other treatments were ineffective or intolerable. This discovery stems from a small clinical trial by scientists at the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, and conducted through a partnership with global biopharmaceutical company AstraZeneca. The results were published online April 3, 2019 in the New England Journal of Medicine.