Seasonal Variability of Exacerbations in Patients With Severe, Uncontrolled Eosinophilic Asthma and Clinical Benefits of Benralizumab: Pooled Analysis of the SIROCCO and CALIMA Trials

Benralizumab is an anti-eosinophilic antibody with demonstrated efficacy for patients with severe, uncontrolled eosinophilic asthma. This study evaluated seasonal variation in the frequency of asthma exacerbations and the reduction of exacerbations with benralizumab treatment for patients with severe, uncontrolled eosinophilic asthma. This was a post-hoc analysis of pooled data from the Phase III SIROCCO (Lancet. 2016;388:2115–27; [N=1,204]) and CALIMA (Lancet. 2016;388:2128–41; [N=1,091]) trials of patients aged 12–75 years receiving high-dosage inhaled corticosteroids/long-acting β2-agonists (ICS/LABA). Patients received benralizumab 30 mg SC every 4 weeks (Q4W) or every 8 weeks (Q8W; first three doses Q4W) or placebo. The primary analysis population was patients receiving high-dosage ICS/LABA with baseline blood eosinophils ≥300 cells/μL. The primary efficacy endpoint was the rate of asthma exacerbations. The observed crude rates of exacerbations for patients with severe, uncontrolled eosinophilic asthma were greater for fall and winter (1.52 and 1.44, respectively) compared with spring and summer (1.11 and 1.02, respectively) for the placebo-treated group. The annual percentage exacerbation rate reduction by season for benralizumab Q8W vs. placebo were spring, 50% (p<0.001); summer, 45% (p<0.001); fall, 46% (p<0.001); and winter, 40% (p<0.001). Similar trends were observed for patients receiving benralizumab Q4W. Benralizumab treatment significantly reduced the frequency of exacerbations compared with placebo in patients with severe, uncontrolled eosinophilic asthma, and this reduction was consistent, with a 40‒50% reduction irrespective of the season.