Mepolizumab therapy in severe asthma – a study of long term efficacy and safety

Abstract

<b>Background:</b> clinical trials demonstrated effectiveness of mepolizumab in treatment of severe eosinophilc asthma, but real world evidence on its longterm outcomes remains limited. <b>Aims:</b> to describe the long-term efficacy and safety of mepolizumab in severe asthma. <b>Methods:</b> patients who had at least one treatment of mepolizumab and follow up data of 2+ years were considered for this study. Clinical and safety outcome were retrieved from the local registry. <b>Results:</b> a total of 66 patients were included [mean age 50 years (range 18-79), 73% females, BMI 32.6±7.3kg/m2, %FEV1 predicted 72.2±22, 59% on maintenance oral corticosteroids (OCS)]. Satisfactory clinical response was observed in 35 (53%) at 12 months, 42 (63.6%) at 18 months, and 41 (62%) at 45months. There was sustained reduction in annual severe exacerbations from 6.7±3.0 to 2.0±2.5 (p &lt;0.001) (figure), and complete wean off maintenance OCS at 45months in 46% patients. Compared to baseline, we observed continued improvement at 45 months in asthma control questionnaire [n=57, 3.35±1.3 vs 2.3±1.4, difference -1.01, p&lt;0.0001), blood eosinophil suppression [n=34, 0.5x109/L (0.35, 0.79) vs 0.04 (0.00, 0.10) p&lt;0.0001], but no change in FeNO [n=17, 52(25.5,98) ppb vs 62 (14.7,105, p=0.5], or FEV1 (data not shown). Of the total stopped treatment (n=25/66), 13/25 (52%) were due to lack of response, and 12/25 (48%) were due to side effects or other causes (e.g. pregnancy). Two patients died from non-mepolizumab/asthma related causes. <b>Conclusion:</b> significant proportion of severe asthma patients had positive sustained response to mepolizumab over follow-up period of 45months. Minority stopped treatment due to lack of response or side effects.