E.1 Medical condition or disease under investigation |
E.1.1 | Medical condition(s) being investigated |
Hypereosinophilic syndrome (HES) |
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E.1.1.1 | Medical condition in easily understood language |
Hypereosinophilic syndrome |
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E.1.1.2 | Therapeutic area | Diseases [C] - Blood and lymphatic diseases [C15] |
MedDRA Classification |
E.1.2 Medical condition or disease under investigation |
E.1.2 | Version | 20.0 |
E.1.2 | Level | PT |
E.1.2 | Classification code | 10048643 |
E.1.2 | Term | Hypereosinophilic syndrome |
E.1.2 | System Organ Class | 10005329 - Blood and lymphatic system disorders |
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E.1.3 | Condition being studied is a rare disease | Yes |
E.2 Objective of the trial |
E.2.1 | Main objective of the trial |
To evaluate the efficacy of mepolizumab SC given every 4 weeks in participants aged 6 to 17 years with HES |
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E.2.2 | Secondary objectives of the trial |
- To assess the effect of mepolizumab SC given every 4 weeks on the change in OCS dose in participants aged 6 to 17 years with HES that are taking OCS at baseline;
- To assess the effect of mepolizumab SC given every 4 weeks on the change in OCS dose in participants aged 6 to 17 years with HES;
- To assess the efficacy of mepolizumab SC given every 4 weeks on fatigue in participants aged 12 to 17 years with HES;
- To evaluate the immunogenicity of mepolizumab SC given every 4 weeks in participants aged 6 to 17 years with HES;
- To assess the effect of long-term use of mepolizumab SC on a PD marker in participants aged 6 to 17 years with HES;
- To assess the PK of mepolizumab SC in participants aged 6 to 17 years with HES |
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E.2.3 | Trial contains a sub-study | Yes |
E.2.3.1 | Full title, date and version of each sub-study and their related objectives |
Optional genetics analysis component assessment |
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E.3 | Principal inclusion criteria |
Age: 1. Participant must be aged 6 to 17 years inclusive, at Screening (Visit 1);
Type of Participant and Disease Characteristics: 2. Participants who have been diagnosed with HES for at least 6 months prior to enrolment (Visit 2); 3. A history of 2 or more HES flares within the past 12 months prior to Screening (Visit 1); 4. Participants must have blood eosinophil count ≥1000 cells/μL present at Screening; 5. Participants must be on a stable dose of HES therapy for the 4 weeks prior to the first dose of mepolizumab (Visit 2);
Sex and Contraceptive/Barrier Requirements: 6. Male and/or female [(according to their reproductive organs and functions assigned by chromosomal complement)] [FDA, 2016].
• Contraception and barriers as well as pregnancy testing is required as appropriate for the age and sexual activity of paediatric participants and as required by local regulations.
A female participant is eligible to participate if she is either: • Premenarcheal or • Not pregnant as confirmed by a negative urine (or serum if required by local regulations) human chorionic gonadotrophin [hCG] test if of reproductive potential.
Females of childbearing potential must commit to consistent and correct use of an acceptable method of contraception (see Section 10.4, Appendix 4 of the study protoocol) for the duration of the trial and 16 weeks after the last dose of investigational product. A urine pregnancy test is required of females of childbearing potential.
Informed Consent and Assent 7. The investigator, or a person designated by the investigator, will obtain written informed consent from each study participant’s (legal guardian as defined in Section 10.1.3 of the study protoocol) and the participant’s assent, when applicable, before any study-specific activity is performed (unless a waiver of informed consent has been granted by an Institutional Review Board [IRB]/Ethics Committee [EC]). All legal guardians should be fully informed, and participants should be informed to the fullest extent possible, about the study in language and terms they are able to understand. 8. The participant capable of providing signed and dated written assent signs and dates a written assent form (age appropriate) and the parent/guardian signs and dates a written informed consent form (ICF) for study participation prior to the initiation of any study-related activities.
Other 9. A legal guardian or primary caregiver must be available to help the study-site personnel ensure follow-up; support the participant to attended assessment days according to the SoA (e.g., able to comply with scheduled visits, treatment plan, laboratory tests, and other study procedures); consistently and consecutively be available to provide information on the participant using the rating scales during the scheduled study visits; accurately and reliably dispense study intervention as directed. |
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E.4 | Principal exclusion criteria |
Participants are excluded from the study if any of the following criteria apply:
Medical Conditions: 1. Life-threatening HES or life-threatening HES co-morbidities: Imminently lifethreatening HES disease severity such that (a) likelihood of death is high unless the course of the disease is interrupted within 12 weeks prior to Visit 2 (b) likelihood of severe deterioration of HES is high unless immediate therapeutic intervention is provided. 2. Other concurrent medical conditions that may affect the participant’s safety: Participants who have 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. 3. Eosinophilia of unknown significance 4. FIP1L1-PDGFRα (F/P) Status: Participants who test positive for F/P 5. Clinical diagnosis of EGPA 6. Infection: • 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). 7. Participants with a known immunodeficiency (e.g., HIV), other than that explained by the use of OCS or other therapy taken for HES. 8. 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. 9. Malignancy: • 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 that had localised carcinoma (i.e., basal or squamous cell) of the skin that was resected for cure will not be excluded. 10. Participants who are not responsive to OCS based on clinical response or blood eosinophil counts.
Prior/Concomitant Therapy: 11. Participants who have previously received mepolizumab in the 4 months prior to enrolment (Visit 2). 12. Participants receiving any of the following: • IV or SC corticosteroids in the 4-week period prior to enrolment (Visit 2). • Any other monoclonal antibodies within 30 days or 5 half-lives, whichever is longer, of enrolment (Visit 2).
Other investigational product/clinical study: 13. 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). The term “investigational” applies to any drug not approved for sale in the country in which it is being used or investigational formulations of marketed products 14. Use of candidate COVID-19 vaccines that have not received limited, accelerated, or full authorisation/approval, and are only in use as part of a clinical trial 15. Participants who are currently participating in any other interventional clinical study
Contraindications: 16. Participants with any history of hypersensitivity to any monoclonal antibody (including mepolizumab)
Other Exclusions: 17. 12-lead ECG finding: For all participants: • An abnormal ECG finding from the 12-lead ECG conducted at Visit 1 if considered to be clinically significant and would impact the participant’s participation during the study based on the evaluation of the investigator. For participants aged 6 to 11 years: • QT interval corrected using Fridericia’s formula (QTcF) > 450 msec. • Left bundle branch block For participant aged 12 to 17 years: • QTcF > 450 msec or QT interval corrected for heart rate (QTc) > 480 msec in participants with bundle branch block 18. Liver abnormality/disease 19. Other laboratory abnormalities |
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E.5 End points |
E.5.1 | Primary end point(s) |
Frequency of HES flares over the 52-week study treatment period |
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E.5.1.1 | Timepoint(s) of evaluation of this end point |
Over the 52-week study treatment period |
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E.5.2 | Secondary end point(s) |
• Change in the mean daily OCS dose (prednisone/prednisolone or equivalent) from Weeks 0 to 4 to Weeks 48 to 52;
• Reduction of ≥50% in mean daily OCS dose (prednisone/prednisolone or equivalent) from Weeks 0 to 4 compared with Weeks 48 to 52;
• Achieving a mean daily OCS dose (prednisone/prednisolone or equivalent) of ≤7.5 mg during Weeks 48 to 52;
• Achieving a mean daily OCS dose (prednisone/prednisolone or equivalent) of ≤7.5 mg during Weeks 48 to 52;
• Change from baseline in fatigue severity based on weekly average score of BFI item 3 (worst level of fatigue during past 24 hours) for Week 52;
• Occurrence of ADA and NAb;
• Ratio to baseline in absolute blood eosinophil count at discrete time points during the 52-week study treatment period;
• Mepolizumab plasma concentration at discrete time points during the 52-week study treatment period |
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E.5.2.1 | Timepoint(s) of evaluation of this end point |
As specified within the list of emdpoints |
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E.6 and E.7 Scope of the trial |
E.6 | Scope of the trial |
E.6.1 | Diagnosis | No |
E.6.2 | Prophylaxis | No |
E.6.3 | Therapy | Yes |
E.6.4 | Safety | Yes |
E.6.5 | Efficacy | Yes |
E.6.6 | Pharmacokinetic | Yes |
E.6.7 | Pharmacodynamic | Yes |
E.6.8 | Bioequivalence | No |
E.6.9 | Dose response | No |
E.6.10 | Pharmacogenetic | No |
E.6.11 | Pharmacogenomic | No |
E.6.12 | Pharmacoeconomic | No |
E.6.13 | Others | Yes |
E.6.13.1 | Other scope of the trial description |
Immunogenicity and optional pharmacogenetic |
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E.7 | Trial type and phase |
E.7.1 | Human pharmacology (Phase I) | No |
E.7.1.1 | First administration to humans | No |
E.7.1.2 | Bioequivalence study | No |
E.7.1.3 | Other | No |
E.7.1.3.1 | Other trial type description | |
E.7.2 | Therapeutic exploratory (Phase II) | No |
E.7.3 | Therapeutic confirmatory (Phase III) | Yes |
E.7.4 | Therapeutic use (Phase IV) | No |
E.8 Design of the trial |
E.8.1 | Controlled | No |
E.8.1.1 | Randomised | No |
E.8.1.2 | Open | Yes |
E.8.1.3 | Single blind | No |
E.8.1.4 | Double blind | No |
E.8.1.5 | Parallel group | No |
E.8.1.6 | Cross over | No |
E.8.1.7 | Other | No |
E.8.2 | Comparator of controlled trial |
E.8.2.1 | Other medicinal product(s) | No |
E.8.2.2 | Placebo | No |
E.8.2.3 | Other | No |
E.8.2.4 | Number of treatment arms in the trial | 1 |
E.8.3 |
The trial involves single site in the Member State concerned
| Yes |
E.8.4 | The trial involves multiple sites in the Member State concerned | No |
E.8.5 | The trial involves multiple Member States | Yes |
E.8.5.1 | Number of sites anticipated in the EEA | 11 |
E.8.6 Trial involving sites outside the EEA |
E.8.6.1 | Trial being conducted both within and outside the EEA | Yes |
E.8.6.2 | Trial being conducted completely outside of the EEA | No |
E.8.6.3 | If E.8.6.1 or E.8.6.2 are Yes, specify the regions in which trial sites are planned |
Argentina |
Brazil |
Israel |
Mexico |
Russian Federation |
Turkey |
United Kingdom |
United States |
Italy |
Netherlands |
Spain |
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E.8.7 | Trial has a data monitoring committee | Yes |
E.8.8 |
Definition of the end of the trial and justification where it is not the last
visit of the last subject undergoing the trial
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E.8.9 Initial estimate of the duration of the trial |
E.8.9.1 | In the Member State concerned years | 1 |
E.8.9.1 | In the Member State concerned months | 6 |
E.8.9.1 | In the Member State concerned days | 7 |
E.8.9.2 | In all countries concerned by the trial years | 2 |
E.8.9.2 | In all countries concerned by the trial months | 10 |
E.8.9.2 | In all countries concerned by the trial days | 18 |