Real World Evidence of Benralizumab in Eosinophilic Severe AsThma in Russia (BEST)

Inclusion Criteria: Subject eligible for enrolment in the study and treatment for benralizumab according to the specific Russian label and in line with reimbursement condition must meet all the following criteria: * Male or female patients older than 18 years with physician's confirmed diagnosis of severe, uncontrolled asthma. * Asthma requiring high-dose ICS plus LABA as maintenance treatment. * Minimum of 2 exacerbations in the last 12 months. Or 1 exacerbation in case that patient had been receiving oral glucocorticoid therapy for at least 6 continuous months directly before enrollment (equivalent to a prednisolone or prednisone dose of 7.5 to 40.0 mg per day) * Documented peripheral blood eosinophil count ≥ 300 cells/μL or ≥150 cells/μL blood in case that patient had been receiving oral glucocorticoid therapy for at least 6 continuous months directly before enrollment (equivalent to a prednisolone or prednisone dose of 7.5 to 40.0 mg per day). * Provision of signed written ICF indicating that they understand the purpose of the study and procedures required for participation in the study. * Patients must be able and willing to read and comprehend written instructions and comprehend and complete the questionnaires required by the protocol (SGRQ, ACQ-5, PGIC and PGIS). Exclusion Criteria: Patients who have previously received benralizumab prior to the start of the study. * Documented lung diseases other than asthma, e.g. COPD, and not within reimbursed label, e.g pregnancy or lactation. * Concomitant treatment with any other biologic for any indication or previous treatment with biology. Acceptable wash-out periods for other asthma biologics: ≥4 month or duration of 5 half-lives from last dose of previous biologic. We choose what is longer the 5 half-life or 4 months. * Currently enrolled in an interventional clinical study in parallel, except: * Patients being in parallel documented in a national asthma registry. * Patients having completed any other clinical trial including those with biologic treatment ≥4 month or duration of 5 half-lives from last dose of previous biologic. We choose what is longer the 5 half-life or 4 months. * An acute or chronic condition that, in the investigator's opinion, would limit the patients' ability to complete questionnaires or participate in this study or impact the interpretations of results.