Long-Term Clinical Outcomes of High-Dose Mepolizumab Treatment for Hypereosinophilic Syndrome

Fei Li Kuang*, Michael P. Fay, Jean Anne Ware, Lauren Wetzler, Nicole Holland-Thomas, Thomas Brown, Hector Ortega, Jonathan Steinfeld, Paneez Khoury, Amy D. Klion

*Corresponding author for this work

Research output: Contribution to journalArticle

27 Scopus citations


Background: Conventional therapies for hypereosinophilic syndromes (HES) have variable efficacy and carry significant long-term toxicities. Anti-IL-5 (mepolizumab) therapy has a glucocorticoid (GC)-sparing effect in GC-sensitive HES, but the efficacy of mepolizumab in treatment-refractory HES patients with severe disease has not been examined to date. Objective: To identify predictors of response to mepolizumab in subjects with severe treatment-refractory HES and compare long-term outcomes in these subjects with HES subjects treated with conventional therapies. Methods: Retrospective analysis of clinical and laboratory data from 35 HES subjects treated with mepolizumab and 55 HES subjects on conventional therapy, all followed at a single center, was performed. Results: Peak eosinophilia, GC sensitivity, pulmonary involvement, HES clinical subtype, and pretreatment serum IL-5 were correlated with mepolizumab response. Despite evidence of more severe disease at baseline, mepolizumab-treated subjects had comparable long-term clinical outcomes to HES subjects treated with conventional therapies and reported improvements in therapy-related comorbidities. Subjects managed with mepolizumab monotherapy had fewer disease flares than HES subjects on conventional therapies or mepolizumab-treated HES subjects requiring additional HES therapies. Conclusions: This study confirms that mepolizumab is an effective and well-tolerated therapy for HES, but suggests that response is more likely in GC-responsive subjects with idiopathic or overlap forms of HES. A primary benefit of treatment is the reduction of comorbidity due to discontinuation or the reduction of conventional HES therapies. Although subjects who completely discontinued GC had the most benefit, high-dose mepolizumab was a safe and effective salvage therapy for severe, treatment-refractory HES.

Original languageEnglish (US)
Pages (from-to)1518-1527.e5
JournalJournal of Allergy and Clinical Immunology: In Practice
Issue number5
StatePublished - Sep 1 2018


  • Eosinophilia
  • Hypereosinophilic syndrome
  • Interleukin 5
  • Monoclonal antibody

ASJC Scopus subject areas

  • Immunology and Allergy

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    Kuang, F. L., Fay, M. P., Ware, J. A., Wetzler, L., Holland-Thomas, N., Brown, T., Ortega, H., Steinfeld, J., Khoury, P., & Klion, A. D. (2018). Long-Term Clinical Outcomes of High-Dose Mepolizumab Treatment for Hypereosinophilic Syndrome. Journal of Allergy and Clinical Immunology: In Practice, 6(5), 1518-1527.e5. https://doi.org/10.1016/j.jaip.2018.04.033