A Phase 2a Study of Benralizumab for Patients with Eosinophilic Asthma in South Korea and Japan

Background: Airway eosinophils are considered to play an important role in the pathogenesis of asthma. Interleukin-5 is believed to be a key cytokine for the development, proliferation and activation of eosinophils. Benralizumab is an anti-interleukin-5 receptor α monoclonal antibody that depletes blood and airway eosinophils. We conducted a phase 2a study in South Korea and Japan to evaluate the effect of benralizumab in an East Asian population. The primary objective was to evaluate the effect of benralizumab in adults with uncontrolled eosinophilic asthma with 2-6 incidences of exacerbations in the past year using a medium/high dose of inhaled corticosteroids and long-acting β 2 -agonists. Methods: This was a multicenter, randomized, double-blind, placebo-controlled study. The subjects (n = 106) were randomized into four groups: placebo (n = 27) or benralizumab 2 mg (n = 27), 20 mg (n = 26) and 100 mg (n = 26). Benralizumab or placebo were administered subcutaneously on weeks 0 (day 1), 4, 8, 16, 24, 32 and 40. The primary endpoint was the asthma exacerbation rate at week 52. Results: The asthma exacerbation rate was reduced by 33, 45 or 36% versus the placebo group when treated with 2, 20 or 100 mg of benralizumab, respectively. The percent mean change in forced expiratory volume at 1 s increased with each of the three doses in subjects treated with benralizumab. Conclusions: Benralizumab reduced asthma exacerbation and improved lung function and asthma control in adults with uncontrolled eosinophilic asthma.