Management of severe allergic asthma in the UK: Which monoclonal antibody would you choose?

Introduction: Omalizumab and Mepolizumab both have approval for use for treatment of severe allergic asthma in corticosteroid dependent patients in the UK. Aims & Objectives: Mepolizumab was most recently approved in April 2017. We wanted to test the hypothesis of why one novel agent may be chosen over another in specialist asthma centres across the UK. We hypothesised that Omalizumab would be the best preferred option. Method: A hypothetical clinical scenario of a severe allergic asthma patient with an accompanying questionnaire was distributed to 48 severe asthma specialists across the UK between August-December 2017. Results: There was a 60% (29) response rate from the 48 letters sent. Omalizumab was first choice in 72% of responses, 24% chose Mepolizumab and 4% chose to increase corticosteroid therapy. The majority selected omalizumab due to having more experience with using this therapy (43%). Other influences included perceiving it was more effective in this case, ease of administration, shorter waiting times, shorter trial period, longer safety and efficacy data and since omalizumab fulfils criteria for the national guidelines. Nasal polyposis, oral corticosteroid sparing effect, mucosal inflammation, meeting the guideline criteria and marked blood eosinophilia were reasons given for choosing mepolizumab. Those choosing omalizumab considered switching to Mepolizumab if the required regimen was 2 weekly or if omalizumab was ineffective after the trial period of 16 weeks (43%). Conclusion: Greater experience with omalizumab was the main influencing factor for specialists when choosing therapy. As the experience with mepolizumab grows in the UK, we expect a shift in this trend.