Mepolizumab benefits severe asthma regardless of medium-dose or high-dose inhaled corticosteroids at baseline

Background Severe asthma treatment commonly entails progression from medium- to high-dose maintenance inhaled corticosteroids (mICS) before biologic therapies are considered. The objective of this post hoc analysis of REALITI-A was to assess the impact of mepolizumab on clinical outcomes when initiated in patients with severe asthma receiving either medium- or high-dose mICS at baseline. Methods REALITI-A (GSK ID: 204710) was a 2-year, prospective observational cohort study enrolling adult patients with asthma receiving newly prescribed mepolizumab 100 mg subcutaneously (index). Data were collected for 12 months before and 24 months following mepolizumab initiation. Outcomes included rate of clinically significant exacerbations (CSEs) requiring systemic corticosteroids and/or emergency department visit/hospitalisation pre- and following mepolizumab, change from baseline (28 days before index) in daily maintenance oral corticosteroid (mOCS) dose to Week 101–104, and change from baseline (90 days before index) in Asthma Control Questionnaire (ACQ)-5 score at Month 24. Results Baseline mICS dose data were available for 774/822 patients. Compared with pre-mepolizumab, the rate of CSEs following mepolizumab reduced by 80% and 73% in the medium- and high-dose mICS subgroups. For patients with baseline mOCS use, median mOCS dose also reduced by 85% and 100% for the medium- and high-dose mICS subgroups, with 45% and 58% of patients discontinuing mOCS. For the medium- and high-dose mICS subgroups, least squares mean ACQ-5 score improved from pre-mepolizumab by 1.57 and 1.55 points. Conclusions Following mepolizumab treatment, patients with severe asthma had reduced CSEs and mOCS dose and improved symptom control, regardless of baseline mICS dose.