STEP: Phase IIIb Study of Benralizumab to Step-down Maintenance Therapy in Patients With Severe Eosinophilic Asthma

Informed Consent 1．Provision of informed consent prior to any study-specific procedures. Written informed consent, and assent when applicable for study participation must be obtained prior to any study related procedures being performed (local regulations are to be followed in determining the assent/consent requirements for children and parent\[s\]/guardian\[s\]) and according to international guidelines and/or applicable local guidelines. Age 2. Patient must be aged 12-75 years old, inclusively, at the time of Visit 1(Week -1 to Week 0) For those patients, who are 17 on the day of Visit 1(Week -1 to Week 0) but will turn 18 after this day, will be considered an adolescent for the purposes of this study. Type of Patient and Disease Characteristics 3. Documented history of physician-diagnosed asthma prior to Visit 1 * Documented post-bronchodilator (post-BD) reversibility in FEV1 of ≥12% and ≥200 mL in FEV1 or positive result of branchial provocation test within 12 months prior to Visit 1. If historical documentation is not available, reversibility must be demonstrated and documented at Visit 1. * Prior to screening (Visit 1, Week -1 to Week 0), patients must have either a documented asthma diagnosis for \>6 months or a history of ICS/LABA use for \>6 months. 4\. Documented diagnosis of severe eosinophilic asthma (EOS≥150 cells/μL at enrollment, and if EOS 150-\<300 cells/μL at enrollment, must have EOS≥300 cells/μL at sometime within 1 year before enrollment) 5. Docume…