Functional respiratory imaging reveals early structural and functional airway responses to benralizumab in severe eosinophilic asthma

BACKGROUND: Benralizumab improves outcomes in severe eosinophilic asthma (SEA). We aimed to evaluate early effects of benralizumab on airway pathophysiology using functional respiratory imaging (FRI). METHODS: In this prospective, single-arm study, 20 adults with SEA underwent CT at baseline, 4 and 12 weeks. Coprimary endpoints were changes in specific airway volume (siVaw) and resistance (siRaw) at functional residual capacity (FRC) and total lung capacity (TLC) at 12 weeks. Imaging outcomes included mucus score/volume and air-trapping. RESULTS: At week 12, siVaw increased at FRC by 0.16 mL/L (27%; 95% CI 0.01% to 0.31%; p = 0.02) and at TLC by 0.14 mL/L (14%; 95% CI 0.03% to 0.25%; p = 0.02); siRaw at TLC decreased by -0.41 kPa·s/L (-24%; 95% CI -0.80% to -0.01%; p = 0.04). siRaw at FRC increased (2.99 kPa·s/L; 95% CI -4.57 to 10.54; p=0.42), with a significant relative change (293%; p=0.03) that lost significance after excluding outliers. siVaw at FRC increased early (week 4: 0.19 mL/L; 33%; 95% CI 0.03% to 0.34%; p = 0.01). At week 12, the mucus score decreased by 0.41 (95% CI -0.67 to -0.14; p