Retrospective real-world study of risk factors for primary resistance to immunotherapy in patients with dMMR/MSI metastatic gastrointestinal cancers

The efficacy of immunotherapy in metastatic dMMR/MSI gastro-intestinal (GI) cancers has led to a rapid increase in the number of patients treated. However, 20-30% of patients experience primary resistance to immune checkpoint inhibitors (ICIPR). A multicenter retrospective real-world study in France investigated factors associated with ICIPR among patients with metastatic dMMR/MSI GI cancers. In multivariable analysis, ICIPR was associated with ECOG performance status ≥ 2 (OR 3.36), liver metastases (OR 2.19), peritoneal metastases (OR 2.00), previous line(s) of therapy (OR 1.83), and age ≤ 50 years (OR 1.76). The authors conclude that these five clinical factors associated with primary resistance to ICIs should be considered to guide treatment choice in GI dMMR/MSI metastatic cancer patients.