Pharmacokinetics and Pharmacodynamics of Mepolizumab Administered Subcutaneously in Children

Inclusion Criteria

• Between 6 and 11 years of age inclusive, at the time of screening.
• Diagnosis of severe asthma, defined by the regional asthma guidelines (i.e., National Institute of Health (NIH), Global Initiative for Asthma (GINA), etc.), for at least 12 months prior to Visit 1. If the participant is naïve to the study site, the participant/guardian must self-report a physician diagnosis of asthma and the investigator must confirm by review of medical history with the participant/guardian.
• Eosinophilic airway inflammation that is related to asthma characterized as eosinophilic in nature as indicated by: elevated peripheral blood eosinophil count of >=300 cells per microliter (cells/μL) demonstrated in the past 12 months OR elevated peripheral blood eosinophil count of >=150/μL at visit 1.
• A well-documented requirement for regular treatment with inhaled corticosteroid (>200 μg/day fluticasone propionate drug powder inhaler [DPI] or equivalent daily) in the 12 months prior to Visit 1 with or without maintenance oral corticosteroids (OCS). The ICS dose should represent medium or high dose in children aged 6-11 years of age [GINA, 2015].
• Current treatment with an additional controller medication for at least 3 months or a documented failure in the past 12 months of an additional controller medication for at least 3 successive months. [e.g., long-acting beta-2-agonist (LABA), leukotriene receptor antagonist (LTRA), or theophylline.]
• Forced expiratory volume in one second (FEV1): Persistent airflow obstruction at either Visit 1 or Visit 2 (FEV1 performed prior to first dose of study medication) as indicated by: A pre-bronchodilator FEV1 2x upper limit of normal (ULN) (isolated bilirubin >1.5xULN is acceptable if bilirubin is fractionated and direct bilirubin <35%) at Visit 1.
• Positive Hepatitis B Surface Antigen or positive Hepatitis C antibody at Visit 1.
• Parent/guardian has a history of psychiatric disease, intellectual deficiency, substance abuse, or other condition (e.g. inability to read, comprehend and write) which will limit the validity of consent to participate in this study.
• Unwillingness or inability of the participant or parent/guardian to follow the procedures outlined in the protocol.
• Participant who is mentally or legally incapacitated.
• Children who are wards of the state or government.
• A participant will not be eligible for this study if he/she is an immediate family member of the participating investigator, sub-investigator, study coordinator, or employee of the participating investigator.
• Omalizumab: Participants who have received omalizumab within 130 days of Visit 1.
• Other Biologics: Participants who have received any biological (other than omalizumab) to treat inflammatory disease within 5 half-lives of visit 1.
• History of sensitivity to any of the study medications, or components thereof or a history of drug or other allergy that, in the opinion of the investigator or Medical Monitor, contraindicates their participation.
• Hypersensitivity: Participants with allergy/intolerance to a monoclonal antibody or biologic.
• The participant has participated in a clinical trial and has received an investigational product within the following time period prior to the first dosing day in the current study: 30 days, 5 half-lives or twice the duration of the biological effect of the investigational product (whichever is longer).