Distinct trajectories of treatment response to mepolizumab toward remission in patients with severe eosinophilic asthma

BACKGROUND: Patients with severe eosinophilic asthma, characterised by a high disease burden, benefit from mepolizumab, which improves symptoms and reduces exacerbations, potentially leading to clinical remission in a subgroup. This study aimed to identify treatment response trajectories to mepolizumab for severe eosinophilic asthma and to assess the achievement of clinical remission. METHODS: Data from the Australian Mepolizumab Registry were used to assess treatment responses at 3, 6 and 12 months. The treatment response trajectories were identified using a group-based trajectory model. The proportions achieving clinical remission at 12 months, which was defined as well-controlled symptoms, no exacerbations and no oral corticosteroid (OCS) use for asthma management, were compared between trajectories, and baseline predictors of the trajectories were identified using logistic regression analysis. RESULTS: We identified three trajectory groups: Group 1, "Responsive asthma with less OCS use" (n=170); Group 2, "Responsive late-onset asthma" (n=58); and Group 3, "Obstructed and less responsive asthma" (n=70). Groups 1 and 2 demonstrated higher proportions achieving clinical remission at 36.5% and 25.9%, respectively, compared to Group 3 with 5.7% (p<0.001). Baseline predictors for assigned groups included lower OCS dose in Group 1; greater forced expiratory volume in 1 s percentage predicted, higher Asthma Quality of Life Questionnaire score, higher OCS dose and nasal polyps in Group 2; with Group 3 as the reference. CONCLUSIONS: Treatment response to mepolizumab in severe eosinophilic asthma follows three trajectories with varying proportions achieving clinical remission and differing baseline characteristics. Treatment response variability may influence the achievement of clinical remission with mepolizumab therapy.