Benralizumab for patients with mild to moderate, persistent asthma (BISE): a randomised, double-blind, placebo-controlled, phase 3 trial.

Background: Benralizumab is a humanised, anti-interleukin 5 receptor α monoclonal antibody that directly and rapidly depletes eosinophils, reduces asthma exacerbations, and improves lung function for patients with severe eosinophilic asthma. The objective of this trial was to assess the safety and efficacy of benralizumab for patients with mild to moderate, persistent asthma.

Methods: In this randomised, double-blind, placebo-controlled, phase 3 trial, we recruited patients aged 18-75 years, weighing at least 40 kg, and with a postbronchodilator reversibility in forced expiratory volume in 1 s (FEV) of at least 12% at screening, from 52 clinical research centres in six countries. Patients must have been receiving either low- to medium-dosage inhaled corticosteroids (ICS) or low-dosage ICS plus long-acting β agonist fixed-combination therapy at screening, had a morning prebronchodilator FEV of more than 50% to 90% predicted at screening, and had one or more of the following symptoms within the 7 days before randomisation: a daytime or night-time asthma symptom score of at least 1 for at least 2 days, rescue short-acting β agonist use for at least 2 days, or night-time awakenings due to asthma for at least one night. We converted patients' ICS treatments to 180 μg or 200 μg budesonide dry powder inhaler twice daily for the entire duration of the study using the approved dosages in the patients' respective countries and randomly allocated them (1:1; stratified by blood eosinophil count [<300 cells per μL vs ≥300 cells per μL] and region [USA vs the rest of the world]) with an interactive web-based voice response system to receive subcutaneous placebo or benralizumab 30 mg injections every 4 weeks for 12 weeks. All patients and investigators involved in patient treatment or clinical assessment and those assessing outcomes were masked to treatment allocation. The primary endpoint was change from baseline prebronchodilator FEV at week 12. Efficacy analyses used an intention to treat approach. This trial is registered with ClinicalTrials.gov, number NCT02322775.

Findings: Between Feb 2, 2015, and April 24, 2015, we enrolled 351 patients, with 211 (60%) randomly assigned (105 [50%] to placebo and 106 [50%] to benralizumab). Benralizumab resulted in an 80 mL (95% CI 0-150; p=0·04) greater improvement (least-squares mean difference) in prebronchodilator FEV after 12 weeks than did placebo (placebo group: 2246 mL [SD 768] at baseline vs 2261 mL [796] at week 12, change from baseline of 0 mL; benralizumab group: 2248 mL [606] vs 2310 mL [670], 70 mL). 44 (42%) patients in the benralizumab group had adverse events compared with 49 (47%) in the placebo group. The most common adverse events for both groups were nasopharyngitis (eight [8%] patients in each group) and upper respiratory tract infections (five [5%] patients in each group). Serious adverse events occurred in two (2%) patients each in the benralizumab (pancytopenia and a suicide attempt, both considered unrelated to treatment) and placebo (cervix carcinoma and colon adenoma) groups.

Interpretation: This study suggests that active and modifiable disease processes might be ongoing in patients with mild to moderate, persistent asthma receiving ICS. Although the lung function improvement observed does not warrant use of benralizumab in this population because it did not reach the minimum clinically important difference of 10%, further studies to assess this finding should be considered.

Funding: AstraZeneca.