A Phase 3 Study to Evaluate the Efficacy and Safety of Benralizumab in Patients With Hypereosinophilic Syndrome (HES)

  • End date
    Aug 13, 2023
  • participants needed
  • sponsor
Updated on 1 August 2021


This is a multicentre, randomised, double-blind (DB), parallel-group, placebo-controlled, 24-week Phase 3 study to compare the efficacy and safety of benralizumab versus placebo administered by SC injection Q4W in patients with hypereosinophilic syndrome (HES). This study comprises 2 distinct periods (together defined as the 'main study'): A 24-week, DB treatment period, during which patients will be randomised to receive either benralizumab or placebo, in addition to prior stable HES background therapy, and an open-label (OLE) treatment period, during which all patients will receive benralizumab. Patients will not continue to be recruited after 47 patients have had their first HES worsening/flare.The primary database lock (DBL) will occur when at least 47 patients have had their first HES worsening/flare event and all randomised patients have been followed up for the 24-week DB treatment period. The target patient population is male and female patients 12 years of age and older with symptomatic active HES. Approximately 120 eligible patients will be randomised at a 1:1 ratio to receive either benralizumab or matching placebo

Condition Hypereosinophilic syndrome
Treatment Placebo, benralizumab
Clinical Study IdentifierNCT04191304
Last Modified on1 August 2021


Yes No Not Sure

Inclusion Criteria

Provision of the signed and dated written informed consent of the patient or the patient's legally authorised representative, and informed assent from the patient (per local regulations) prior to any mandatory study-specific procedures, sampling, and analyses
Males and females 12 years of age and older at the time of signing the ICF
Documented diagnosis of HES (history of persistent eosinophilia >1500 cells/L without secondary cause on 2 examinations [interval 1 month; Valent et al 2012] and evidence of end organ manifestations attributable to the eosinophilia)
Documented negative testing for the FIP1L1-PDGFRA fusion tyrosine kinase gene translocation
Stable HES treatment dose(s) and regimen for 4 weeks at the time of Visit 1
Signs or symptoms of HES worsening/flare and/or laboratory abnormalities indicative of HES worsening/flare (other than isolated eosinophilia) at Visit 1
AEC 1000 cells/L at Visit 1 (assessed by local laboratory)
Corticosteroid responsiveness defined as an AEC <1000 cells/L after a 2-day course of OCS 1 mg/kg/day at Visit 2 (assessed by local laboratory)
Women of childbearing potential (WOCBP) must agree to use a highly effective method of birth control (confirmed by the Investigator) from enrolment, throughout the study duration, and within 12 weeks after last dose of IP and have a negative urine dipstick pregnancy test result on Visit 1

Exclusion Criteria

Life-threatening HES and/or HES complication(s) as judged by the Investigator
Medical intervention for HES-related life-threatening event(s) within 12 weeks prior to randomisation OR
History of thrombotic complications, stroke, or significant cardiac damage related to HES, if the respective events were life threatening and currently represent a risk of life-threatening disease complications. Events that occurred in the past but considered resolved or stable, can be accepted if, as per Investigator's judgment participation in the study will not put the patient at risk
Disease severity that, in the opinion of the Investigator, makes the patient inappropriate for inclusion in the study
Presence of FIP1L1-PDGFRA fusion tyrosine kinase gene translocation or other known imatinib-sensitive mutation
Definitive diagnosis of eosinophilic granulomatosis with polyangiitis
Known, pre-existing, clinically significant endocrine, autoimmune, metabolic, neurological, renal, gastrointestinal, hepatic, haematological, respiratory, or any other system abnormalities that are not associated with HES and are uncontrolled with standard treatment which, in the opinion of the Investigator, may put the patient at risk because of his/her participation in the study, or may influence the results of the study, or the patient's ability to complete the entire duration of the study
Hypereosinophilia of unknown significance
Cardiovascular: Documented history of any clinically significant cardiac damage, clinically significant echocardiography (if available) or ECG findings within 12 months prior to Visit 1 or clinically significant ECG findings at screening that, in the opinion of the Investigator, may put the patients at risk
Known currently active liver disease
Chronic stable hepatitis B and C (including positive testing for hepatitis B surface antigen or hepatitis C antibody) or other stable chronic liver disease are acceptable if patient otherwise meets eligibility criteria. Stable chronic liver disease should generally be defined by the absence of ascites, encephalopathy, coagulopathy, hypoalbuminemia, oesophageal or gastric varices, or persistent jaundice, or cirrhosis
Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) level 3 the upper limit of normal (ULN) during the screening period (AST or ALT >5ULN if documented HES with liver manifestations). Transient increase of AST/ALT level that resolves by the time of randomisation is acceptable if, in the Investigator's opinion, the patient does not have an active liver disease and meets other eligibility criteria
Current malignancy, or history of malignancy, except
Patients who have had basal cell carcinoma, localised squamous cell carcinoma of the skin, or in situ carcinoma of the cervix are eligible provided the patient is in remission and curative therapy was completed at least 12 months prior to the date that informed consent, and assent when applicable, was obtained
Patients who have had other malignancies are eligible provided the patient is in remission and curative therapy was completed at least 5 years prior to the date informed consent, and assent when applicable, was obtained
Diagnosis of systemic mastocytosis
Chronic or ongoing active infections requiring systemic treatment, as well as clinically significant viral, bacterial, or fungal infection within 4 weeks prior to Visit 1
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