Real-World Effectiveness of Mepolizumab in Severe Asthma: Results from the Multi-country, Self-controlled Nucala Effectiveness Study (NEST)

The Nucala Effectiveness Study (NEST) assessed the effectiveness of mepolizumab in patients with severe asthma (SA) in countries previously underrepresented in real-world studies.

A multi-country, bi-directional, self-controlled, observational cohort study conducted in Colombia, Chile, India, Türkiye, Saudi Arabia, United Arab Emirates, Kuwait, Oman, and Qatar. Historical and/or prospective data from patients with SA were assessed 12 months pre- and post-mepolizumab initiation. Primary endpoint: incident rate ratio (IRR) of clinically significant exacerbations (CSEs). Key secondary endpoints: healthcare resource utilisation (HCRU), oral corticosteroid (OCS) use, lung function and symptom control (Asthma Control Test [ACT] scores).

Overall, 525 patients with SA burden pre-initiation (geometric mean blood eosinophil count [BEC] 490.7 cells/µl; 31.4% prior biologic use; 37.3% obese) received at least one dose of mepolizumab 100 mg subcutaneously. Post-initiation, a significant reduction in CSEs was observed (76% [p < 0.001]; IRR [95% confidence interval] 0.24 [0.19–0.30]); 72.0% of patients had no CSEs. Mepolizumab treatment led to a reduction in OCS use (52.8% pre-initiation vs. 16.6% post-initiation) and a mean (standard deviation [SD]) change in OCS dose of − 18.1 (20.7) mg post-initiation; 36.1% of patients became OCS-free. Fewer patients were hospitalised post-initiation (22.5% pre-initiation vs. 6.9% post-initiation). Improvements in mean (SD) forced expiratory volume in 1 s (62.8 [20.2]% pre-initiation vs. 73.0 [22.7]% post-initiation) and ACT scores (15.0% pre-initiation vs. 64.5% of patients post-initiation with well-controlled asthma) were observed. Proportion of patients with BEC ≥ 500 cells/µl decreased from 84.4% pre-initiation to 18.1% post-initiation.

Mepolizumab was effective in reducing the burden of SA by significantly reducing CSEs, reducing OCS use and HCRU, and improving lung function and asthma control, which could translate to improvements in health-related quality of life in patients with SA and high OCS dependency in the countries studied. A graphical abstract is available with this article.