In China, severe asthma (SA) with eosinophilic phenotype prevalence is rising yet treatment options are limited. Mepolizumab is the first targeted biologic therapy for eosinophilic-driven disease in China. This study (NCT03562195) evaluated efficacy and safety of mepolizumab in Chinese patients with SA.The Phase III, multi-center, randomised, placebo-controlled, double-blind, parallel-group study enrolled patients ≥12 years of age with SA, with ≥2 exacerbations in the previous year, and on inhaled corticosteroids (ICS) plus ≥1 controller medication. Following 1–4-week run-in, patients were randomised 1:1 to mepolizumab 100 mg or placebo subcutaneously every 4 weeks for 52 weeks. Primary endpoint: annualised rate of clinically significant exacerbations (CSEs) through Week 52. Secondary endpoints: time-to-first-CSE, frequency of CSEs requiring hospitalisation/emergency department visits or hospitalisation over 52 weeks; mean change in St George's Respiratory Questionnaire (SGRQ) total score and pre-bronchodilator forced expiratory volume in one second (FEV1) at Week 52; safety was evaluated.The modified intent-to-treat population included 300 patients. At Week 52 with mepolizumabversusplacebo, annualised rate of CSEs was 65% lower (0.45versus1.31 events/year; rate ratio [95% CI]: 0.35 [0.24, 0.50];p<0.001), time-to-first CSE longer (hazard ratio [95% CI]: 0.38 [0.26, 0.56];p<0.001), and number of CSEs requiring hospitalisation/emergency department visit lower (rate ratio [95% CI]: 0.30 [0.12, 0.77]; p=0.012). From baseline to Week 52, SGRQ score improved (p=0.001) and pre-bronchodilator FEV1increased (p=0.006). Adverse event incidence was similar between treatment groups.Mepolizumab provided clinical benefits to patients with SA in China and showed a favorable benefit-risk profile.