PERIPHERAL BLOOD EOSINOPHIL SHIFTS IN SEVERE, UNCONTROLLED ASTHMA

Abstract

Introduction Greater clarity is needed on peripheral blood eosinophil counts (BEC) associated with events such as exacerbations or responsiveness to biologics in severe asthma. Inclusion criteria and prespecified analyses on peripheral BECs vary between clinical trials. Stability of BEC on repeated measures in this population is unknown. We examined shifts in BEC in patients with severe, uncontrolled asthma despite high-dosage inhaled corticosteroids/long-acting β2-agonists. Methods BEC shift was examined in patients randomized to placebo in two Phase III studies, SIROCCO (NCT01928771; 48 weeks) and CALIMA (NCT01914757; 56 weeks). We grouped patients by baseline BEC and counted the number in each baseline group who had ≥1 recorded peripheral BEC and who then shifted BEC group during the trial. Results 141 patients receiving placebo had a baseline peripheral BEC <150 cells/μL. Of these, 70.2% (n=99) had ≥1 BEC ≥150 cells/μL and 34.8% (n=49) had a BEC ≥300 cells/μL. An additional 170 patients had a baseline peripheral BEC 150≤300 cells/μL. Of these, 62.4% (n=106) had ≥1 BEC ≥300 cells/μL. 428 patients had a baseline peripheral BEC ≥300 cells/μL. Of these, 52.8% (n=226) had ≥1 BEC <300 cells/μL, and 22.4% (n=96) had a BEC <150 cells/μL (figure). Conclusions Most patients with a baseline BEC <150 cells/µL during SIROCCO or CALIMA, and approximately one-third had at least one BEC measurement ≥300 cells/µL. The data suggest that a single BEC does not negate the possibility of a patient having eosinophil-driven disease. Performing additional BECs may be of benefit. Percentage of Patients with Shifts in Peripheral Blood Eosinophil Count Group After Baseline Greater clarity is needed on peripheral blood eosinophil counts (BEC) associated with events such as exacerbations or responsiveness to biologics in severe asthma. Inclusion criteria and prespecified analyses on peripheral BECs vary between clinical trials. Stability of BEC on repeated measures in this population is unknown. We examined shifts in BEC in patients with severe, uncontrolled asthma despite high-dosage inhaled corticosteroids/long-acting β2-agonists. BEC shift was examined in patients randomized to placebo in two Phase III studies, SIROCCO (NCT01928771; 48 weeks) and CALIMA (NCT01914757; 56 weeks). We grouped patients by baseline BEC and counted the number in each baseline group who had ≥1 recorded peripheral BEC and who then shifted BEC group during the trial. 141 patients receiving placebo had a baseline peripheral BEC <150 cells/μL. Of these, 70.2% (n=99) had ≥1 BEC ≥150 cells/μL and 34.8% (n=49) had a BEC ≥300 cells/μL. An additional 170 patients had a baseline peripheral BEC 150≤300 cells/μL. Of these, 62.4% (n=106) had ≥1 BEC ≥300 cells/μL. 428 patients had a baseline peripheral BEC ≥300 cells/μL. Of these, 52.8% (n=226) had ≥1 BEC <300 cells/μL, and 22.4% (n=96) had a BEC <150 cells/μL (figure). Most patients with a baseline BEC <150 cells/µL during SIROCCO or CALIMA, and approximately one-third had at least one BEC measurement ≥300 cells/µL. The data suggest that a single BEC does not negate the possibility of a patient having eosinophil-driven disease. Performing additional BECs may be of benefit.