Mepolizumab response in patients with COPD and an eosinophilic phenotype with/without chronic bronchitis (CB): A METREX/METREO post hoc analysis

<bold>Background:</bold> Mepolizumab reduced annual moderate/severe exacerbation rates (AER) vs placebo in COPD with an eosinophilic phenotype in the METREX/METREO Phase 3 trials (<ext-link>NCT02105948</ext-link>/NCT02105961). <bold>Aims and Objectives:</bold> To assess mepolizumab efficacy in COPD with an eosinophilic phenotype with/without CB symptoms. <bold>Methods:</bold> Post hoc analysis of METREX/METREO in those with a screening blood eosinophil count (BEC; cells/µL) ≥300 receiving mepolizumab (100 mg SC) or placebo Q4W for 52 weeks, with/without CB symptoms based on SGRQ. Endpoints included AER at Week 52, COPD Assessment Test (CAT) responders (≥2-point improvement), CAT score change from baseline at Weeks 48–52, and SGRQ responders (≥4-point reduction) at Week 52. <bold>Results:</bold> At baseline, 161/456 (35%) and 175/455 (38%) in mepolizumab and placebo groups had a screening BEC ≥300 and available data to assess CB symptoms. Of these, 99/161 (61%) and 115/175 (66%) reported CB symptoms, respectively. AER with mepolizumab vs placebo was 1.32 vs 1.73 (rate ratio [95% CI]: 0.76 [0.56, 1.03]) with CB and 1.25 vs 1.63 (0.76 [0.51, 1.14]) without. CAT patient responder rates were 53% vs 40% with CB (OR [95% CI]: 1.71 [0.97, 3.01]) and 28% vs 34% (0.57 [0.24, 1.35]) without. Difference in change in CAT score (95% CI) was -1.9 (−3.7, −0.1) with CB and −0.5 (−2.8, 1.7) without. SGRQ responders totalled 48% vs 36% for mepolizumab vs placebo with CB (OR [95% CI]: 1.63 [0.93, 2.84]), and 48% vs 50% without (0.94 [0.42, 2.10). <bold>Conclusions:</bold> Mepolizumab reduced exacerbations regardless of CB symptoms, while CAT and SGRQ responses were more pronounced in patients with CB.