Gut Microbiome and Immunotherapy in Advanced Non-Small Cell Lung Cancer: A Prospective Cohort Study

This prospective observational study examined the gut microbiome (GM) of 50 advanced Non-Small Cell Lung Cancer (NSCLC) patients in North India initiating immune checkpoint inhibitor (ICI) therapy, aiming to assess its impact on treatment response in a non-Western population. Shotgun metagenomic sequencing was performed on stool samples collected at baseline and the first on-treatment timepoint, with analyses focusing on alpha and beta diversity, and differential abundance between responders and non-responders. The study's key findings revealed a Prevotella-dominant baseline microbiota, consistent with regional profiles, and found no significant differences in diversity or clear responder-specific signatures between patient groups. This absence of a clear biomarker was further supported by the fact that nominal enrichments of beneficial taxa in responders did not survive FDR correction. The overall conclusion is that GM-based biomarker discovery and interventions for immunotherapy must be contextualized to local populations due to significant regional differences in baseline gut ecology.