Mepolizumab Demonstrates Quantifiable Reduction in Corticosteroid-Related Adverse Effects in Severe Asthma

BACKGROUND: Treatment which reduces systemic corticosteroid (SCS)-related adverse effects but maintains disease control is of broad public health importance. OBJECTIVE: To evaluate the effect of mepolizumab versus chronic-SCS use on SCS-related adverse effects in patients with severe asthma. METHODS: This retrospective, longitudinal cohort study (GSK ID: US 218950) used claims data from the Optum Clinformatics Data Mart database from November 2014 - December 2022. Eligible patients (aged ≥12 years with ≥2 asthma diagnostic claims), had ≥2 mepolizumab claims (mepolizumab-treated cohort) or ≥6 months continuous SCS use (chronic-SCS-treated cohort). Inverse probability of treatment weighting was used to balance cohort characteristics. PRIMARY OUTCOME: SCS-related adverse effects. SECONDARY OUTCOMES: exacerbation frequency, SCS/oral corticosteroid (OCS) use, healthcare resource utilization (HCRU), and costs (excluding cost of therapy). RESULTS: Overall, 1,219 (mepolizumab-treated) and 835 (chronic-SCS-treated) patients with severe asthma were included (median follow-up 12 months). Cohorts were well-balanced after weighting (mean age 63-65 years, 66% female). The mepolizumab-treated cohort had significant reductions in overall, acute, and chronic-SCS-related adverse effects (rate ratio [RR] [95% confidence interval] 0.80 [0.70-0.92], 0.63 [0.47-0.84], 0.80 [0.70-0.92], respectively) versus the chronic-SCS-treated cohort; SCS dose reduction of 4.7 mg/day corresponds to a 20% reduction in SCS-related adverse effects (p=0.002). Similar trends were observed in exacerbation rates, HCRU, and medical costs, although not all reached statistical significance. CONCLUSION: Mepolizumab treatment reduced acute and chronic corticosteroid effects in patients with severe asthma versus chronic-SCS use, suggesting avoidance of corticosteroid use can lead to measurable regression of SCS-associated adverse effects and more favorable disease trajectory.