Success of biologics in patients with co-morbid severe asthma and COPD – do we need a more individualised definition of success?

<bold>Introduction:</bold> Monoclonal antibodies (MAbs) for asthma are being trialled in COPD, but trial data suggests MAb success will differ in COPD patients compared to asthma. We retrospectively reviewed asthma patients with concurrent COPD started on a MAb at our centre. <bold>Methods:</bold> Patients commenced on a MAb for asthma who also had COPD (physician diagnosed, post-bronchodilator ratio <0.7 and a significant pack year smoking history (PYH)) in 2022 and 2023 were retrospectively reviewed. <bold>Results:</bold> 6% (23/375) of patients approved for a MAb for asthma had concurrent COPD. Mean age was 68 years (SD 11), 61% (14/23) female; 87% (20/23) were ex-smokers with a mean PYH of 42. 15/23 (65%) patients started on Benralizumab, 5/23 (22%) on Tezepelumab, and 3/23 (13%) on Mepolizumab. 83% (19/23) were starting a MAb for the first time. Patients were symptomatic (mean ACQ-6 4.2, SD 0.8) and had reduced lung function (mean FEV1 51% predicted, SD 17%, and DLCO 60% predicted, SD 17%) at baseline. Annualized exacerbation frequency (AER) was 6.4 (SD 3). At 12 months, mean ACQ-6 was 3.7 (SD 1.6) and the average reduction in AER was 46% (SD 39%). 39% (9/23) demonstrated successful reduction in AER (defined as >50%) and over half (57%, 13/23) continued their biologic beyond 12 months, despite not all meeting the asthma criteria to continue. <bold>Conclusion:</bold> Patients with severe asthma and COPD may see a lower reduction in AER compared to the standard asthma success criteria, but this may still be clinically meaningful and compares to studies investigating biologics in COPD. A lower success threshold could be considered in patients with asthma and COPD.