Redefining the lung function parameters in assessing clinical remission of severe asthma with mepolizumab treatment: A post-hoc analysis of the REDES study

16 Nov 2023


Recent developments in precision medicine and the use of biologics to treat chronic inflammatory diseases, including severe asthma, have led to on-treatment clinical remission (CR) being a plausible treatment goal.1 However, despite the general consensus to evolve the definition of CR in severe asthma from single clinical outcomes to composite measures, the specific outcomes to be included have not been confirmed.1 In this presentation, a post hoc analysis was conducted on the REDES study to assess the impact of including different lung function parameters as the fourth component of CR outcome.1

The REDES study was a retrospective, real-world, phase 4, observational study which enrolled 318 adult patients with severe eosinophilic asthma across 24 Spanish hospitals.1 Patients were initiated on mepolizumab and had key clinical information available ≥12 months prior to enrollment.1 These patients received 100mg of mepolizumab subcutaneously (SC) on top of the  standard-of-care therapy and were followed up every 6 months for ≥12 months.1

The primary endpoint of the post-hoc analysis was the proportion of patients achieving 4-component clinical remission  52 weeks after mepolizumab initiation which included oral corticosteroid (OCS)-free, exacerbation-free, Asthma Control Test (ACT)  score ≥20, and one of the prespecified lung function parameters.1


Primary endpoint:
  • The primary endpoint was the proportion of patients achieving 4-component clinical remission 52 weeks after mepolizumab initiation1
  • The inclusion of a lung function parameter reflects a more stringent criteria, with marginally fewer patients defined to be in CR1
  • Similar outcomes were observed when using the ≥80% predicted post-bronchodilator (BD) forced expiratory volume in 1 second (FEV1) and the ≤50mL worsening from baseline in post-BD FEV1 parameters, which may reflect the natural lung function loss that occurs annually with age in individuals without lung disease1
  • The addition of ≥80% predicted post-BD FEV1 criteria to the composite 3-component definition reduced the proportion of patients with clinical remission at week 52 from 37% (n=96/260) to 30% (n=43/144)1
  • With the incorporation of change from baseline in post-BD FEV1 categories, the proportion of patients achieving clinical remission increased sequentially at 22% (n=28/125), 27% (n=34/125), 30% (n=38/125), and 31% (n=39/125) corresponding to a definition of ≥100mL improvement, ≥0mL improvement, ≤50mL worsening, and ≤100mL worsening respectively1


"These findings support clinical remission in severe asthma as  a realistic real-world goal and should aid the development of  a standardized definition of asthma remission on therapy."

Dr. Christian Domingo Ribas
Universitat Autonoma de Barcelona,
Barcelona, Spain


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