Abstract Rationale Benralizumab has shown efficacy in reducing background therapy in patients with severe eosinophilic asthma (SEA) in global studies. STEP is the first study investigating the background therapy step-down in SEA patients treated with benralizumab in China. This interim analysis of STEP evaluated the efficacy and safety of benralizumab after 16-week treatment. Methods STEP (NCT06465485) is a single-arm, phase IIIb trial conducted across 76 Chinese sites, from which SEA patients aged 12-75 years with ≥1 exacerbation in the prior year and receiving stable medium- or high-dose (MD/HD) inhaled corticosteroids-long-acting β2-agonist (ICS-LABA) for ≥2 month were enrolled. Leukotriene receptor antagonists (LTRA) and long-acting anti-muscarinic (LAMA) were allowed for patients receiving MD ICS-LABA. Benralizumab 30 mg was injected subcutaneously at Week 0, 4, 8 and every eight weeks thereafter. Efficacy outcomes (Asthma Control Questionnaire-5 ACQ-5 score, pre-bronchodilator forced expiratory volume in one second pre-BD FEV₁ and St. George’s Respiratory Questionnaire SGRQ score) and safety outcomes were evaluated. Results From February 28, 2024 to March 18, 2025, 504 patients were enrolled, including 127 patients receiving MD ICS-LABA, 126 receiving MD ICS-LABA plus LTRA, 126 receiving MD ICS-LABA plus LAMA, 110 receiving HD ICS-LABA and 15 receiving other background therapies. All patients received ≥1 dose of benralizumab. At Week 16, mean (SD) ACQ-5 score was 0.76 (0.78) (change from baseline: −0.73 1.03), with 84.5% (398/471) of patients achieving ACQ-5 score 1.5 and 55.0% (259/471) of patients achieving ACQ-5 score 0.75. Mean (SD) pre-BD FEV₁ was 2.36 L (0.83) (change from baseline: 0.19 L 0.46). Mean (SD) SGRQ score was 22.6 (19.5) (change from baseline: −17.0 22.8). During Week 0-16, mean (SD) number of asthma exacerbation was 0.1 (0.3), and 95.3% (466/489) of patients were exacerbation-free. Similar improvement was observed across subgroups of patients receiving different background therapies, as summarized in Table. Overall, adverse events (AEs) occurred in 78.2% (395/504) of patients during Week 0-16, with 22.0% (111/504) being benralizumab-related. Serious AEs occurred in 15.1% (76/504) of patients, among which 2.4% (12/504) were benralizumab-related. Seven patients (1.4%) discontinued benralizumab due to AEs and no death due to AEs occurred. Conclusions In Chinese patients with SEA and receiving MD/HD ICS-LABA as background therapy, 16-week benralizumab treatment led to improvement in symptom control, lung function and health-related quality of life. The improvement was consistent among patients receiving different background therapies. Benralizumab treatment showed a favourable safety profile in these patients, consistent with global findings. This abstract is funded by: AstraZeneca China
Zhang et al. (Fri,) studied this question.