S19 Objective assessment of cough: an early marker of response to biological therapies in asthma?

Aims Cough is an important symptom in asthma. The objective assessment of chronic cough has been enhanced by the development of validated ambulatory cough monitoring systems and this form of assessment may represent the best global objective synthesis, compared to other forms of objective and subjective assessment of cough. Mepolizumab is a novel drug which binds to and inactivates interleukin-5 and has been demonstrated to reduce exacerbations in eosinophilic asthmatics in the long term. We postulated that objective measurement of cough could potentially act as a rapidly responsive, objective and clinically relevant endpoint for establishing the effectiveness of this class of drugs. Methods Consecutive consenting patients being initiated on treatment with mepolizumab had a 24 hour cough count recorded at baseline, a day prior to initiation of therapy. This was repeated 1, 3 and 6 months later. Cough recording was done using the validated Hull Automated Cough Counter. Asthma control was assessed via the asthma control questionnaire (ACQ). Demographic data is presented descriptively. Paired t-test was used to look for analysis and missing values were imputed from preceding data. Results Eleven subjects (8 females) with a mean age of 53.6 years had a baseline cough count recorded. Mean 24 hour cough count was 172.4 at baseline. At 1, 3 and 6 months following initiation of treatment the 24 hour cough count fell to a mean of 101.4, 92 and 70.8 respectively (figure 1). Area under the curve of cough counts on treatment was significantly improved over baseline (p Conclusion We demonstrate clear improvement in objective cough count at one month following initiation of treatment with mepolizumab, which is sustained over 6 months, in patients with uncontrolled eosinophilic asthma. Objective cough measurement could be used as an early, precise and clinically relevant endpoint in both the assessment of response to therapy as well as future drugs development.