Predictive Signature of Benralizumab Response

Inclusion Criteria: * Patients between 18 and 75 years old. * Patients diagnosed with severe asthma (Chung and al, Eur Respir J 2014), i.e.: * asthma requiring high doses of ICS (\>1000 microgram per day of Beclomethasone or equivalent) associated with LABA and/or systemic corticosteroids to be controlled over one year, * and/or uncontrolled asthma despite the later medications, * and/or a controlled asthma worsening after decreasing medications, * Documented historical reversibility of FEV1 ≥12% and FEV1 gain ≥ 200 milliliter * ACQ-7 score ≥ 1,5 at M0. * ≥ 3 exacerbations in the 12 months prior to screening visit M-1. * Eosinophil blood count ≥ 0,3 G/L at inclusion visit or in the 12 months prior to the inclusion visit. If eosinophil blood count is ≥ 0,15 G/L and \< 0,3 G/L, an eosinophilic phenotype defined by at least 1 of the following criteria will be required: * Fractional Exhaled Nitric Oxide (FeNO) \> 25 ppm at inclusion visit or in the 12 months prior to the inclusion visit. * Sputum eosinophils ≥ 3% at inclusion visit or in the 12 months prior to the inclusion visit. * Patients who provide written informed consent prior to participation in the study Exclusion Criteria: * Patients diagnosed with difficult-to-treat asthma and/or with uncontrolled asthma differential diagnosis according to the judgment of the investigator (e.g., vocal cord dysfunction, gastroesophageal reflux disease, granulomatous eosinophilic vasculitis, obstructive sleep apnea syndrome, hyperventilation syndrome, allergic broncho-pulmonary aspergillosis, Carrington disease, DIPNECH, asthma/COPD overlap syndrome). * Non-adherent patients to inhaled treatment (ICS + LABA). * Active smokers or former smokers exceeding 20 packs year. * Exacerbation at inclusion visit M0. * Active malignancy or malignancy in remission over less than 5 years. * Active parasitic infection or parasitic infection in the past 24 weeks. * Hypersensitivity to Benralizumab or to any of the excipients of Fasenra® (histidine, histidine hydrochloride monohydrate, trehalose dihydrate, polysorbate 20) * Patients requiring other immunosuppressive and immunomodulator drugs * Patients requiring other biotherapy than Benralizumab, with or without French's marketing authorisation in severe asthma * Patients requiring other biotherapy than Benralizumab that affects the immune system * SARS-COV2 infection * Pregnancy, lactation, or patients with childbearing potential refusing efficient contraceptive method. * Patients under psychiatric condition altering their comprehension and their ability to give informed consent. * Patients already enrolled in a clinical interventional research. * Patients not affiliated to a health insurance plan * Patients under guardianship, curators or safeguard of justice