- Life-threatening EGPA: Imminently life-threatening EGPA disease defined as any of the following within 3 months prior to Screening (Visit 1); Intensive care required; Severe alveolar haemorrhage or haemoptysis requiring transfusion or ventilation or haemoglobin < 8 gram per liter (g/dL) (<80 g/L) or drop in haemoglobin > 2 g/dL (>20 g/L) over a 48 hour period due to alveolar haemorrhage; Rapidly progressive glomerulonephritis (RPGN) with creatinine > 2.5 milligram per deciliter (mg/dL) (>221 µmol/L) or rise in creatinine > 2 mg/dL (>177 µmol/L) over a 48 hour period; Severe gastrointestinal (GI) involvement, e.g., gangrene, bleeding requiring surgery; Severe central nervous system (CNS) involvement; Severe cardiac involvement, e.g., life-threatening arrhythmia, cardiac failure: ejection fraction < 20%, New York Heart Association Class III/IV (as discussed in protocol), acute myocardial infarction.