Anti-IL-5 and anti-IL-5R biologics for severe asthma. Are there any differences in their effects?

The aim of this retrospective multicentre study is to describe the clinical characteristics of patients diagnosed with severe eosinophilic asthma receiving anti-IL-5/anti-IL-5Rα therapies and to compare their effectiveness.

We collected and analysed results separately for anti-IL-5 and anti-IL-5Rα therapies from January 2016 until December 2021 in multidisciplinary severe asthma units. We collected demographic and clinical data, treatment with previous anti-IgE and/or anti-IL-5 agents, and comorbidities. We compared the number of exacerbations and admissions to the hospital, daily oral corticosteroid intake, pulmonary function tests, and Asthma Control Test scores before and after 12 months of therapy. 261 patients were included: 176 patients in the anti-IL-5 group and 85 in the anti-IL-5Rα group.

Both groups led to statistically significant reductions in asthma exacerbations, hospital admissions, and visits to the Emergency Room. Although both groups showed a significant reduction in blood eosinophiliccount, we found a difference, although not significant, in the magnitude of reduction as benralizumab was able to decrease eosinophil counts to zero. Patients in the anti-IL-5 group achieved higher ACT scores after treatment, although this improvement was seen in both treatment groups.

The anti-IL-5 and anti-IL-5Rα biologics have shown similar effectiveness despite having different mechanisms of action. The anti-IL-5 group appeared to be better than benralizumab at improving ACT scores and FEV1/FVC and at reducing the number of inhalers. Although these differences were not statistically significant, it is not clear whether they may have clinical relevance and they might highlight the need for further head-to-head studies comparing these treatments.