Response to IL-5/IL-5R Antagonists and Remission Rate in Patients With Severe Asthma Who Would Have Been Excluded From the Pivotal Clinical Trials.

Abstract

Randomized controlled trials (RCTs) assessing the efficacy of IL-5/IL-5R antagonists showed a significant reduction in asthma exacerbations as well as a corticosteroid-sparing effect in selected patients with severe eosinophilic asthma. To compare the response and remission rate after treatment with IL-5/IL-5R antagonists in patients with asthma who would or would not have met inclusion criteria of pivotal RCTs. This was a retrospective cohort study of patients with severe eosinophilic asthma aged 18 and older treated with IL-5/IL-5R antagonists between 2012 and 2020 in a tertiary outpatient asthma clinic. Patients aged 75 years or younger, with a smoking history of less than 10 pack-years and a reversible FEV₁ less than 80% predicted in the previous year were considered to fulfill the pivotal RCT inclusion criteria. Response to treatment and clinical remission of asthma were assessed in those who did or did not fulfill pivotal RCT inclusion criteria. A total of 108 subjects were included. Only 22 patients (20.4%) met all pivotal RCT inclusion criteria. There was no significant difference in response to treatment of these patients compared with those who did not fulfill inclusion criteria (odds ratio [95% CI] = 0.66 [0.15-2.85]). However, RCT eligibility was associated with a higher likelihood of achieving clinical remission (odds ratio [95% CI] = 4.09 [1.02-16.45]). IL-5/IL-5R antagonists seem to be as effective in subjects who would have been excluded from pivotal RCTs as in those who met the RCT inclusion criteria, but RCT eligibility increases the likelihood of achieving clinical remission of asthma.