Benralizumab for the add-on maintenance treatment of patients with severe asthma aged 12 years and older with an eosinophilic phenotype

[Biologics in severe childhood asthma]

INTRODUCTION

Severe asthma in children remains relatively rare. It is no longer considered as a single disease but rather as a syndrome corresponding to different phenotypes and distinct pathophysiological pathways. Various biomarkers can contribute to phenotyping, essentially specific IgE test results, blood eosinophil counts, the exhaled fraction of NO (FeNO) assay, as well as deep lung biomarkers from induced sputum, bronchoalveolar lavage or bronchial biopsy.

STATE OF KNOWLEDGE

In children, the biologics currently approved for severe asthma are omalizumab, mepolizumab and dupilumab from the age of 6, and tezepelumab from the age of 12.

PERSPECTIVES

Benralizumab and tezepelumab offer promising perspectives and a pediatric extension could be of interest in future treatment of severe pediatric asthma.

CONCLUSIONS

Based on physiopathological mechanisms, biologics represent a new and promising approach in the treatment of asthma. That said, the long-term efficacy and impact of these treatments on the natural history of the disease require further investigation. It is of paramount importance to take into account the specificities of pediatric asthma and, more particularly, to conduct clinical trials in younger patients.

Challenges in the Pharmacotherapeutic Management of Pediatric Asthma

Bronchial asthma is one of the most common chronic conditions in pediatric practice, with increasing prevalence hampered by poor socioeconomic impacts, leading to major public health issues. Considered as a complex heterogeneous syndrome, not a single disease, the management of the disease is a real challenge, impacting medical staff, patients and caregivers. Over the decades, a significant number of diagnostic and treatment regimen have been developed to achieve good standards, sustaining balanced control of the disease. This paper attempts a review on the establishment of new trends in the management of bronchial asthma in the pediatric age group.

Phenotypic and functional translation of IL33 genetics in asthma

BACKGROUND

Asthma is a complex disease with multiple phenotypes that may differ in disease pathobiology and treatment response. IL33 single nucleotide polymorphisms (SNPs) have been reproducibly associated with asthma. IL33 levels are elevated in sputum and bronchial biopsies of patients with asthma. The functional consequences of IL33 asthma SNPs remain unknown.

OBJECTIVE

This study sought to determine whether IL33 SNPs associate with asthma-related phenotypes and with IL33 expression in lung or bronchial epithelium. This study investigated the effect of increased IL33 expression on human bronchial epithelial cell (HBEC) function.

METHODS

Association between IL33 SNPs (Chr9: 5,815,786-6,657,983) and asthma phenotypes (Lifelines/DAG [Dutch Asthma GWAS]/GASP [Genetics of Asthma Severity & Phenotypes] cohorts) and between SNPs and expression (lung tissue, bronchial brushes, HBECs) was done using regression modeling. Lentiviral overexpression was used to study IL33 effects on HBECs.

RESULTS

We found that 161 SNPs spanning the IL33 region associated with 1 or more asthma phenotypes after correction for multiple testing. We report a main independent signal tagged by rs992969 associating with blood eosinophil levels, asthma, and eosinophilic asthma. A second, independent signal tagged by rs4008366 presented modest association with eosinophilic asthma. Neither signal associated with FEV₁, FEV₁/forced vital capacity, atopy, and age of asthma onset. The 2 IL33 signals are expression quantitative loci in bronchial brushes and cultured HBECs, but not in lung tissue. IL33 overexpression in vitro resulted in reduced viability and reactive oxygen species-capturing of HBECs, without influencing epithelial cell count, metabolic activity, or barrier function.

CONCLUSIONS

We identify IL33 as an epithelial susceptibility gene for eosinophilia and asthma, provide mechanistic insight, and implicate targeting of the IL33 pathway specifically in eosinophilic asthma.