Patient Stratification

Patient Stratification refers to the process of dividing patient populations into subgroups based on shared biological, clinical, or molecular characteristics that influence disease behaviour, treatment response, or safety risk, enabling more precise therapeutic decision-making and improving clinical trial success rates. Stratification criteria may include genetic mutations, biomarker expression levels, disease stage, immune signatures, comorbidities, or pharmacogenomic variants.

The biopharmaceutical industry increasingly depends on patient stratification to optimise clinical development, particularly in oncology and immunology where heterogeneous patient responses often determine trial outcomes. Biomarker-driven stratification enriches trials for responders, improving statistical power and reducing sample sizes while supporting regulatory approval through demonstrating clear benefit in defined populations. Companion diagnostics frequently enable stratified medicine by identifying patients eligible for targeted therapies such as EGFR inhibitors in lung cancer or HER2-targeted treatments in breast cancer. Stratification also supports safety by identifying patients at higher risk of adverse events. Challenges include biomarker validation, assay standardisation, and ensuring stratification strategies remain clinically meaningful. As precision medicine expands through genomics, proteomics, and real-world data integration, patient stratification continues shaping modern drug development and clinical practice.