Health outcomes after stopping long-term mepolizumab in severe eosinophilic asthma: COMET

Asthma worsening and symptom control are clinically important health outcomes in patients with severe eosinophilic asthma. This analysis of COMET evaluated whether stopping versus continuing long-term mepolizumab therapy impacted these outcomes. Patients with severe eosinophilic asthma with ⩾3 years continuous mepolizumab treatment (via COLUMBA (NCT01691859) or COSMEX (NCT02135692) open-label studies) were eligible to enter COMET (NCT02555371), a randomised, double-blind, placebo-controlled study. Patients were randomised 1:1 to continue mepolizumab 100 mg subcutaneous every 4 weeks or to stop mepolizumab, plus standard of care asthma treatment. Patients could switch to open-label mepolizumab following an exacerbation. Health outcome endpoints included time to first asthma worsening (composite endpoint: rescue use, symptoms, awakening at night and morning peak expiratory flow (PEF)), patient and clinician assessed global rating of asthma severity and overall perception of response to therapy, and unscheduled healthcare resource utilisation. Patients who stopped mepolizumab showed increased risk of and shorter time to first asthma worsening compared with those who continued mepolizumab (hazard ratio (HR) 1.71; 95% CI 1.17–2.52; p=0.006), including reduced asthma control (increased risk of first worsening in rescue use (HR 1.36; 95% CI 1.00– 1.84; p=0.047) and morning PEF (HR 1.77; 95% CI 1.21–2.59; p=0.003). There was a higher probability of any unscheduled healthcare resource use (HR 1.81; 95% CI 1.31–2.49; p<0.001), and patients and clinicians reported greater asthma severity and less favourable perceived response to therapy for patients who stopped versus continued mepolizumab. These data suggest that patients with severe eosinophilic asthma continuing long-term mepolizumab treatment sustain clinically important improvements in health outcomes.