A new treatment for a rare blood disorder



PDGFRA-negative hypereosinophilic syndrome is a chronic and debilitating disorder with limited and ineffective treatment options that tend to have significant side effects. It’s one of a group of rare disorders characterized by an excess of eosinophils, a type of white blood cell, in the blood and bodily tissues. Patients with the illness face substantial and long-term clinical manifestations that can include intractable itch, digestive problems, heart complications, and blood clots.


IRP researchers led by Amy Klion, M.D., completed a randomized, double-blind, placebo-controlled, Phase 2 clinical trial assessing the ability of a therapeutic called benralizumab to destroy eosinophils. Benralizumab, which targets a receptor found on the surface of human eosinophils, was highly effective in reducing eosinophil levels in blood and tissue while presenting few or no toxic effects in patients with a severe hypereosinophilic syndrome that is resistant to currently available treatments.


The discovery of a potentially effective therapy for the illness that has limited side effects will allow patients to taper down other treatments that have substantial long-term toxic effects.


Kuang FL, Legrand F, Makiya M, Ware JA, Wetzler L, Brown T, Magee T, Piligian B, Yoon P, Ellis JH, Sun X, Panch SR, Powers A, Alao H, Kumar S, Quezado M, Yan L, Lee N, Kolbeck R, Newbold P, Goldman M, Fay MP, Khoury P, Maric I, Klion AD. (2019). Benralizumab for PDGFRA-Negative Hypereosinophilic Syndrome. N Engl J Med. Apr 4;380(14):1336-1346.

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This page was last updated on Friday, June 9, 2023