A Trial of Mepolizumab Adjunctive Therapy for the Prevention of Asthma Exacerbations in Urban Children

Asthma is a growing problem, especially in children. It causes frequent wheezing, shortness of breath, chest tightness, and cough. Asthma attacks, or exacerbations, are problems for children with asthma. The purpose of this study is to see if treatment with a medication called mepolizumab (Nucala®), given along with standard asthma care, makes children less likely to have asthma attacks. Mepolizumab is a new drug that is approved by the Food and Drug Administration (FDA) for use in children with asthma who are aged 12 years and older. Mepolizumab is given by injection. It is being studied by other researchers in children aged 6-11 years. All participants will be prescribed standard asthma medications by a clinician who is trained in asthma care. Medications will include controller medications, a rescue medication, and a medication for severe asthma attacks (prednisone). The amount of medication that participants receive may be increased or decreased during the study based on their symptoms and breathing test results. Study clinicians will treat all participants according to the same guidelines. These treatment guidelines are based on recommendations from a group of national experts in asthma. This study has been designed this way so that all participants will have safe and effective standard asthma care. In order to enroll in this study, participants must be willing to have their asthma managed by the study clinician during the entire study period. Participants must also be willing to bring study medications to all study visits. This study will include up to 20 study visits. Participant involvement in the study will endure for approximately 1 year. During the treatment period, participants will be placed in one of two treatment groups: * Mepolizumab injection and guidelines-based asthma care or * Placebo injection and guidelines-based asthma care. Participants will not be able to choose which group they are assigned. This assignment is random and by chance, much like flipping a coin. Participants will not know if they are receiving mepolizumab or placebo. Investigators will compare the study results between the participants of each group.