Document Type


Original Publication Date


Journal/Book/Conference Title

The New England Journal of Medicine



DOI of Original Publication



Originally Published at

This article was updated on June 5, 2008 at The correction was published as follows:

Treatment of Patients with the Hypereosinophilic Syndrome with Mepolizumab (Original Article, N Engl J Med 2008:358;1215 1228) . In Figure 2D, the x axis should have been labeled “Days” (rather than “Week”), and in Figure 2E, the y axis should have been labeled “Proportion of Intention-to-Treat Population without Treatment Failure” (rather than “with Treatment Failure”). We regret the errors. The figure has been corrected on the Journal's Web site at

Date of Submission

January 2015



The hypereosinophilic syndrome is a group of diseases characterized by persistent blood eosinophilia, defined as more than 1500 cells per microliter with end-organ involvement and no recognized secondary cause. Although most patients have a response to corticosteroids, side effects are common and can lead to considerable morbidity.


We conducted an international, randomized, double-blind, placebo-controlled trial evaluating the safety and efficacy of an anti–interleukin-5 monoclonal antibody, mepolizumab, in patients with the hypereosinophilic syndrome. Patients were negative for the FIP1L1–PDGFRA fusion gene and required prednisone monotherapy, 20 to 60 mg per day, to maintain a stable clinical status and a blood eosinophil count of less than 1000 per microliter. Patients received either intravenous mepolizumab or placebo while the prednisone dose was tapered. The primary end point was the reduction of the prednisone dose to 10 mg or less per day for 8 or more consecutive weeks.


The primary end point was reached in 84% of patients in the mepolizumab group, as compared with 43% of patients in the placebo group (hazard ratio, 2.90; 95% confidence interval [CI], 1.59 to 5.26; P


Our study shows that treatment with mepolizumab, an agent designed to target eosinophils, can result in corticosteroid-sparing for patients negative for FIP1L1– PDGFRA who have the hypereosinophilic syndrome. ( number, NCT00086658.)


From The New England Journal of Medicine, Rothenberg, M. E., Klion, A. D., Roufosse, F. E. et al., Treatment of Patients with the Hypereosinophilic Syndrome with Mepolizumab. Vol. 358, Page 1215, Copyright © 2008 Massachusetts Medical Society.

Is Part Of

VCU Internal Medicine Publications

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Supplementary Appendix