D2.173 - Real-World Evidence From the TYREX Study on the effectiveness of Mepolizumab in patients with severe asthma and clinically relevant aeroallergen sensitization

Atopy is present in the majority of patients with asthma, with prevalences around 70–80% among asthmatics versus roughly 50% in the general population, depending on age and atopy definition. These data highlight the important role of allergy in the development of severe asthma (SA), which can act as an initial trigger, maintaining its influence throughout the course of the disease. This study evaluates the effectiveness of mepolizumab in atopic patients with clinical manifestations related to their sensitization

TYREX is a multicenter, retrospective, observational study that recruited patients with severe asthma treated with mepolizumab for ≥12 months and up to >5 years.

For this post hoc analysis, patients were stratified according to the presence or absence of clinically relevant aeroallergen sensitization. Patient characteristics were described at baseline, and comparisons of clinical outcomes were performed at 12 months and at the end of follow-up including clinical remission defined as zero exacerbations, no maintenance OCS, ACT ≥20, and FEV₁ ≥80% predicted.

Of the 446 patients included in the TYREX study, 115 had allergic sensitization associated with asthma baseline symptoms.

As expected, baseline total IgE levels were higher in the allergic group. Both allergic and non-allergic patients showed a marked, statistically significant reduction in blood eosinophil counts and FeNO levels over the follow-up period.

Annual exacerbation rates were reduced by more than 80% in each group, with no relevant differences observed between them. A significant oral corticosteroid–sparing effect was also evident across the populations. Sustained and clinically meaningful improvements in asthma control (ACT) were achieved in all cases (Table 1).

Post-bronchodilator lung function (FEV1 and % predicted) and small airway function (FEF25–75) also improved significantly in both groups, with greater consistency in non-allergic patients. The proportion of patients achieving clinical remission was comparable regardless of allergic status. The mean FEOS ratio at the end of follow-up was also similar between allergic and non-allergic patients, with no statistically significant difference (Table 1). 

In the TYREX study, mepolizumab demonstrated comparable effectiveness across all parameters, regardless of the presence of allergic sensitization associated with symptoms. These findings support IL-5 inhibition as an effective therapeutic approach for patients with uncontrolled severe allergic asthma