French National Study on Predictive Factors of Resistance to Pembrolizumab Immunotherapy in MSI Metastatic Colorectal Cancer

What this Trial Is About

Researchers are investigating factors that predict resistance to pembrolizumab, an immunotherapy drug used as the first treatment in patients with metastatic colorectal cancer that shows microsatellite instability or deficient mismatch repair. This study follows up on findings that about 20-30% of patients treated with pembrolizumab show primary resistance, highlighting a need to better identify which patients will benefit from this therapy and which may need other treatments. This research involves a national French cohort called CORESIM, combining both retrospective and prospective patient groups. Patients who started pembrolizumab treatment since February 2021 are included retrospectively, while new patients beginning pembrolizumab from February 2024 will be enrolled prospectively. Tumor samples and blood will be collected to analyze predictive biomarkers. The study expects to include about 600 patients over a 2-year enrollment period. Participants will be followed for 3 years to monitor outcomes and gather data on pembrolizumab resistance. Tumor archives and blood samples will be collected to support the research. The primary goal is to identify factors linked to treatment resistance. The study is observational, meaning it tracks patients receiving standard care without assigning treatments. This long-term follow-up helps researchers understand how different factors affect response to pembrolizumab in metastatic colorectal cancer.

Prospective National Cohort Evaluating Predictive Biomarkers of Resistance to Immunotherapy in Patients With MSI/dMMR Metastatic Colorectal Cancer (CORESIM)