The Role of ACT Score in Mepolizumab Discontinuation

Background Mepolizumab is a therapy for severe asthma. However, studies on mepolizumab with external validity and diverse population from the US are lacking. There is little knowledge of the characteristics of people that discontinue mepolizumab in clinical care. Objective To investigate the real-world efficacy and time to clinical discontinuation of mepolizumab, we evaluated individuals with asthma started on mepolizumab at the Cleveland Clinic. We hypothesized that there are characteristics that distinguish which patients would remain on mepolizumab and which patients would discontinue the medication. Methods Between 2016 and 2022, patients who started on mepolizumab consented to be assessed over 18 months. At baseline, a questionnaire including demographic and medical history was collected. Laboratory findings such as ACT score, F E NO (Fractional Excretion of Nitric Oxide), and spirometry were recorded. At the conclusion of the observation period, the participants were divided into two categories: Group A and Group B. Results Group B [N=28] discontinued mepolizumab ( P < 0.05) at an average of 5.8 months (SD 4.2 months). Group A [N=129] stayed on the therapy for at least 1 year. A participant with an ACT score less than 13 has an odds ratio of 6.64 (95% CI, 2.1 – 26.0) of discontinuing mepolizumab therapy. For a male, the odds of discontinuing mepolizumab therapy is 3.39 (95% CI, 1.1 – 11.2). Conclusion In this real-world study, we find that high eosinophil count may not be adequate in screening which individuals will benefit from mepolizumab. Up to 17% of patients fail therapy within 6 months, with male sex and low ACT score increasing risk of mepolizumab discontinuation at Cleveland Clinic.