Biomarkers for severe eosinophilic asthma

Area of Science:

• Pulmonology
• Pharmacology
• Biomarker Research

Background:

• Severe asthma treatment has advanced with targeted biologics.
• Understanding endotypes and phenotypes is crucial for effective therapy.
• Mepolizumab is a biologic targeting eosinophilic inflammation in severe asthma.

Purpose of the Study:

• To review the role of eosinophil counts as biomarkers for mepolizumab efficacy.
• To establish criteria for selecting patients likely to benefit from mepolizumab.
• To highlight blood eosinophil counts as a predictive biomarker.

Main Methods:

• Review of evidence from the mepolizumab clinical development program.
• Analysis of pharmacodynamic and predictive biomarker data.
• Evaluation of eosinophil counts in blood, sputum, and tissue.

Main Results:

• Blood eosinophil counts, not sputum or tissue, emerged as a reliable biomarker.
• Mepolizumab efficacy is predicted by specific blood eosinophil thresholds.
• A baseline threshold of ≥150 cells/μL or historical ≥300 cells/μL identifies likely responders.

Conclusions:

• Blood eosinophil counts are validated pharmacodynamic and predictive biomarkers for mepolizumab.
• Specific blood eosinophil thresholds aid in patient selection for mepolizumab therapy.
• This approach optimizes treatment outcomes for severe eosinophilic asthma.