Mepolizumab in Hypereosinophilic Syndrome: A Systematic Review and Meta-analysis

Clinics (Sao Paulo). 2021 Oct 11:76:e3271. doi: 10.6061/clinics/2021/e3271. eCollection 2021.


We aimed to evaluate the efficacy and safety of mepolizumab (MEP) in the management of hypereosinophilic syndrome (HES). A systematic search was performed, and articles published until March 2021 were analyzed. The primary efficacy results evaluated were hospitalization rate related to HES, morbidity (new or worsening), relapses/failure, treatment-related adverse effects, prednisone dosage ≤10 mg/day for ≥8 weeks, and eosinophil count <600/μL for ≥8 weeks. A meta-analysis was conducted, when appropriate. Three randomized controlled trials (RCTs), with a total of 255 patients, were included. The studies contemplated the use of MEP 300 mg/SC or 750 mg/IV. According to the evaluation of the proposed outcomes, when relapse rates/therapeutic failures were assessed, there was a 26% reduction with MEP 300 mg/SC (RD=-0.26; 95% CI: -0.44 to -0.08; p=0.04) and 48% reduction with MEP 750 mg/IV (RD=-0.48; 95% CI: -0.67, -0.30; p<0.00001). For the outcomes, prednisone dosage ≤10 mg/day for ≥8 weeks was 48% (RD=0.48; 95% CI: 0.35 to 0.62; p<0.00001), and the eosinophil count <600/μL for ≥8 weeks was 51% (RD=0.51; 95% CI: 0.38 to 0.63; p<0.00001), both showed a reduction with MEP 300 mg/IV and 750 mg/IV. No statistically significant differences in treatment-related adverse effects outcomes were observed for either dosage (RD=0.09; 95% CI: -0.05 to 0.24; p=0.20; RD=0.09; 95% CI: -0.11 to 0.29; p=0.39). Despite the positive effects observed for the studied outcomes, the exact significance remains unclear.

Publication types

  • Meta-Analysis
  • Systematic Review

MeSH terms

  • Antibodies, Monoclonal, Humanized* / therapeutic use
  • Humans
  • Hypereosinophilic Syndrome* / drug therapy
  • Leukocyte Count
  • Prednisone / therapeutic use


  • Antibodies, Monoclonal, Humanized
  • mepolizumab
  • Prednisone