Cessation Versus Continuation of Long-term Mepolizumab in Severe Eosinophilic Asthma Patients

Study Summary

Primary objective of the study is to evaluate whether patients with severe eosinophilic asthma who have received long-term treatment with mepolizumab (at least 3 years) need to maintain treatment with mepolizumab to continue to receive benefit. Subjects who participated in the open-label studies MEA115666 or 201312 with at least 6 months of treatment with mepolizumab prior to Visit 1 and who have no more than 2 consecutive missed doses of mepolizumab treatment will be eligible to participate in this study. This study will be conducted in 4 parts in approximately 300 subjects. Part A will be Variable Open-Label Run-in (for subjects with less than 3 years of mepolizumab treatment). Once the required 3 year exposure is reached, subjects will enter Part B- Fixed Open-Label Run-In (4 weeks to 8 weeks). During Part A and B subjects will be administered Open-label mepolizumab (100 milligram \[mg\] Subcutaneous \[SC\]) every 4 weeks. Part C will be the randomized double-blinded part. Upon completion of Part B, eligible subjects will be randomized to mepolizumab (100 mg SC) every 4 weeks or placebo administered SC every 4 weeks for 52 weeks. Subjects discontinuing investigational product (IP) due to a clinically significant asthma exacerbation will then enter optional Part D of the study. During Part D, subjects receive open-label mepolizumab in addition to their standard of care therapy for the remainder of the study, through Part D up to 52-weeks post-randomization. An Exit Visit will be conducted 52 weeks after randomization in order to assess subject's efficacy parameters, immunogenicity status, and to conduct additional safety assessments. Eligible subjects will participate in the study ranging from 56 to192 weeks, depending on the duration of Part A (0 to 132 weeks) and Part B (4 to 8 weeks).

Primary Outcome

Clinically significant exacerbation was defined as worsening of asthma which requires use of systemic corticosteroids (e.g., prednisone) for at least 3 days or a single intramuscular (IM) corticosteroid dose and/or hospitalization and/or emergency department (ED) visits. For participants on maintenance systemic corticosteroids, at least double the existing maintenance dose for at least 3 days is required. Percentage of participants with clinically significant exacerbation over time during the on

Interventions

• DRUG Placebo
• BIOLOGICAL Mepolizumab 100mg