Life-threating Asthma Exacerbation Successfully Treated with Benralizumab.

A 52-year-old Japanese man with a history of childhood asthma presented at our emergency department with progressive dyspnea. Despite subcutaneous adrenaline injections, salbutamol nebulization, and intravenous methylprednisolone, the carbon dioxide partial pressure (pCO2) increased to 110 mmHg. The patient was intubated, and mechanical ventilation was initiated because of severe respiratory failure. Severe bronchospasm frequently occurs despite appropriate treatment. Therefore, we decided to administer biologics. After the administration of a single dose of benralizumab, his respiratory condition improved, with normalization of pCO2, tidal volume, and airway resistance. We successfully extubated the patient two days after the administration of benralizumab.