An International, Retrospective Study of Off-Label Biologic Use in the Treatment of Hypereosinophilic Syndromes

Michael M. Chen, Florence Roufosse, Sa A. Wang, Srdan Verstovsek, Sandy R. Durrani, Marc E. Rothenberg, Thanai Pongdee, Joseph Butterfield, Timothy Lax, Michael E. Wechsler, Miguel L. Stein, Princess U. Ogbogu, Basil M. Kahwash, Sameer K. Mathur, Dagmar Simon, Praveen Akuthota, Nicole Holland, Lauren Wetzler, Jean Anne M. Ware, Canting GuoMichael P. Fay, Paneez Khoury, Amy D. Klion, Bruce S. Bochner*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Background: Treatment of hypereosinophilic syndrome (HES) often requires the use of immunomodulators with substantial side effect profiles. The emergence of biologics offers an alternative treatment modality. Objective: To examine real-world practice data to describe the safety and consequences of various biologics suspected to directly or indirectly affect eosinophilic inflammation for the treatment of HES. Methods: Retrospective data from 13 centers were collected via an online Research Electronic Data Capture repository. Inclusion criteria included (1) peripheral eosinophil count of 1,500/mm3 or greater without a secondary cause; (2) clinical manifestations attributable to the eosinophilia; and (3) having received mepolizumab (anti-IL-5), benralizumab (afucosylated anti-IL-5 receptor α), omalizumab (anti-IgE), alemtuzumab (anti-CD52), dupilumab (anti-IL-4 receptor α), or reslizumab (anti-IL-5) outside a placebo-controlled clinical trial. Results: Of the 151 courses of biologics prescribed for 121 patients with HES, 59% resulted in improved HES symptoms and 77% enabled tapering of other HES medications. Overall, 105 patients were receiving daily systemic glucocorticoids at the time of a biologic initiation and were able to reduce the glucocorticoid dose by a median reduction of 10 mg of daily prednisone equivalents. Biologics were generally safe and well-tolerated other than infusion reactions with alemtuzumab. Thirteen of 24 patients had clinical improvement after switching biologics and nine patients responded to increasing the dose of mepolizumab after a lack of response to a lower dose. Conclusions: Biologics may offer a safer treatment alternative to existing therapies for HES, although the optimal dosing and choice for each subtype of HES remain to be determined. Limitations of this study include its retrospective nature and intersite differences in data collection and availability of each biologic.

Original languageEnglish
Pages (from-to)1217-1228.e3
JournalJournal of Allergy and Clinical Immunology: In Practice
Issue number5
StatePublished - May 2022


FundersFunder number
Belgian National Fund for Scientific Research Grants F
Cincinnati Children's Hospital.B.S
Mapi Research Trust
Revolo Biotherapeutics
National Institutes of HealthT32AI083216
National Institute of Allergy and Infectious DiseasesZIAAI001130
Johns Hopkins University
American Partnership for Eosinophilic Disorders
Fonds De La Recherche Scientifique - FNRS5/4/150/5, FC 54372


    • Biologic
    • Eosinophil
    • Eosinophilic granulomatosis with polyangiitis
    • Hypereosinophilic syndrome


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