Last updated: 04/14/2026 06:06:07
Study in Pediatrics with HypEREosinophilic syndrome (SPHERE)SPHERE
EudraCT ID
Not applicable
EU CT Number
Not applicable
Trial status
Completed
Completed
Trial overview
Official title: A Phase 3, 52-week, open-label, single arm study to investigate the efficacy and safety of mepolizumab SC in participants aged 6 to 17 years with hypereosinophilic syndrome
Trial description: The purpose of this study is to investigate the efficacy and safety of mepolizumab in children and adolescents with hypereosinophilic syndrome (HES) who are receiving standard of care (SoC) therapy.
Primary purpose:
Treatment
Trial design:
Single Group Assignment
Masking:
None (Open Label)
Allocation:
Randomized
Primary outcomes:
Number of participants who experienced HES flares over the 52-Week study treatment period
Timeframe: Up to Week 52
Secondary outcomes:
Change in mean daily oral corticosteroids (OCS) dose (prednisone/prednisolone or equivalent) for each 4-week period from Weeks 0-4 to Weeks 48-52
Timeframe: Baseline (Weeks 0-4), Weeks 4-8, Weeks 8-12, Weeks 12-16, Weeks 16-20, Weeks 20-24, Weeks 24-28, Weeks 28-32, Weeks 32-36, Weeks 36-40, Weeks 40-44, Weeks 44-48 and Weeks 48-52
Number of participants with reduction of >=50 percentage (%) in mean daily OCS dose (prednisone/prednisolone or equivalent) for each 4-week period from Weeks 0-4 to Weeks 48-52
Timeframe: Baseline (Weeks 0-4), Weeks 4-8, Weeks 8-12, Weeks 12-16, Weeks 16-20, Weeks 20-24, Weeks 24-28, Weeks 28-32, Weeks 32-36, Weeks 36-40, Weeks 40-44, Weeks 44-48 and Weeks 48-52
Number of participants with a mean daily OCS dose (prednisone/prednisolone or equivalent) of less than or equal to (<=) 7.5 milligrams (mg) during Weeks 48-52 in subpopulation of participants that were taking OCS at Baseline
Timeframe: Weeks 48-52
Number of participants with a mean daily OCS dose (prednisone/prednisolone or equivalent) of <=7.5 mg during Weeks 48-52 in overall population
Timeframe: Weeks 48-52
Change from Baseline in fatigue severity based on weekly average score of Brief Fatigue Inventory (BFI) Item 3 (worst level of fatigue during past 24 hours) for Week 52 for participants in the age group of 12 to 17 years
Timeframe: Baseline (Week 0) and Week 52
Number of participants with any time post-Baseline positive Anti-mepolizumab antibodies (ADA)
Timeframe: Up to Week 52
Number of participants with any time post-Baseline positive neutralizing antibodies (NAb)
Timeframe: Up to Week 52
Ratio to Baseline in blood eosinophil count
Timeframe: Baseline (Week 0), Weeks 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48 and 52
Plasma concentrations of Mepolizumab
Timeframe: Pre-dose at Weeks 4 and 24; Week 52
Interventions:
Drug: Mepolizumab
Enrollment:
16
Observational study model:
Not applicable
Primary completion date:
2025-28-10
Time perspective:
Not applicable
Clinical publications:
Not applicable
Medical condition
Hypereosinophilic Syndrome
Product
mepolizumab
Collaborators
NA
Study date(s)
July 2022 to October 2025
Type
Interventional
Phase
3
Participation criteria
Sex
Female & Male
Age
6 - 17 Years
Accepts healthy volunteers
No
- Participant must be aged 6 to 17 years inclusive, at Screening (Visit 1).
- Participants who have been diagnosed with HES for at least 6 months prior to enrolment (Visit 2).
- Life-threatening HES or life-threatening HES co-morbidities
- Other concurrent medical conditions that may affect the participant’s safety
Inclusion and exclusion criteria
Inclusion criteria:
- Participant must be aged 6 to 17 years inclusive, at Screening (Visit 1).
- Participants who have been diagnosed with HES for at least 6 months prior to enrolment (Visit 2).
- A history of 2 or more HES flares within the past 12 months prior to Screening (Visit 1).
- Participants must have blood eosinophil count >=1000 cells per microliter (/mcL) present at Screening.
- Participants must be on a stable dose of HES therapy for the 4 weeks prior to the first dose of mepolizumab (Visit 2)
- Male and/or female
- Signed written informed consent
Exclusion criteria:
- Life-threatening HES or life-threatening HES co-morbidities
- Other concurrent medical conditions that may affect the participant’s safety
- Eosinophilia of unknown significance
- Fusion tyrosine kinase gene translocation [FIP1L1- Platelet-derived Growth Factor Receptor (PDGFRα) (F/P)] positivity
- Clinical diagnosis of eosinophilic granulomatosis with polyangiitis (EGPA)
- Participants with chronic or ongoing active infections requiring systemic treatment, as well as participants who have experienced clinically significant infections due to viruses, bacteria, and fungi within 4 weeks prior to enrolment (Visit 2)
- Participants with a pre-existing parasitic infestation within 6 months prior to enrolment (Visit 2)
- Participants with a known immunodeficiency (e.g. Human immunodeficiency virus [HIV]), other than that explained by the use of OCS or other therapy taken for HES
- Participants with documented history of any clinically significant cardiac damage prior to Screening (Visit 1) that, in the opinion of the investigator, would impact the participant’s participation during the study
- Participants with a history of or current lymphoma, Participants with current malignancy or previous history of cancer in remission for less than 12 months prior to Screening (Visit 1)
- Participants who are not responsive to OCS based on clinical response or blood eosinophil counts.
- Participants who have previously received mepolizumab in the 4 months prior to enrolment (Visit 2)
- Participants receiving non-oral systemic corticosteroids in the 4-week period prior to enrolment (Visit 2).
- Participants who have received any other monoclonal antibodies within 30 days or 5 half-lives, whichever is longer, of enrolment (Visit 2).
- Participants who have received treatment with an investigational agent (biologic or non-biologic) within the past 30 days or 5 drug half-lives, whichever is longer, prior to enrolment (Visit 2).
- Use of candidate Coronavirus disease 2019 (COVID-19) vaccines that have not received limited, accelerated, or full authorization/approval, and are only in use as part of a clinical trial.
- Participants who are currently participating in any other interventional clinical study
- Participants with any history of hypersensitivity to any monoclonal antibody (including mepolizumab).
- Evidence of clinically significant abnormality in the hematological, biochemical, or urinalysis screen from the sample collected at Screening (Visit 1), that could put the participant’s safety at risk by participating in the study, as judged by the investigator
Trial location(s)
Study documents
Protocol
Available language(s): English
Statistical analysis plan
Available language(s): English
If you wish to request for full study report, please contact - [email protected]
Results overview
Results posted on ClinicalTrials.gov
Recruitment status
Completed
Actual primary completion date
2025-28-10
Actual study completion date
2025-28-10
Plain language summaries
Summary of results in plain language
Available language(s): English, Arabic (Israel), Dutch, Hebrew, Italian, Portuguese (Brazil), Russian (Israel), Spanish (Argentina), Spanish (Mexico), Spanish, Turkish
To view plain language summaries on trialsummaries.com click here.
Additional information about the trial
Additional information
Not applicable
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