Gut microbial structural variation associates with immune checkpoint inhibitor response

Area of Science:

• Microbiome research
• Genomics
• Cancer immunotherapy

Background:

• The gut microbiota's role in therapeutic resistance and toxicity of immune checkpoint inhibitors (ICIs) is recognized.
• The impact of genomic variations within gut bacteria on ICI efficacy remains largely unexplored.
• Subtle genomic differences in bacterial strains can lead to significant phenotypic changes.

Purpose of the Study:

• To systematically identify microbial genomic structural variants (SVs) in the gut microbiome.
• To investigate the association between identified SVs and patient outcomes in ICI therapy.
• To explore the link between SVs, treatment response, survival, and immune-related adverse events.

Main Methods:

• Utilized gut microbiome data from 996 patients across seven clinical trials.
• Employed SGV-Finder for systematic identification of microbial genomic structural variants (SVs).
• Conducted metagenome-wide association analysis to explore SV associations with clinical endpoints.
• Replicated findings across different patient cohorts.

Main Results:

• Identified specific microbial SVs associated with response, progression-free survival, and overall survival.
• Found associations between SVs and immune-related adverse events.
• Associated SVs were detected in key species like *Akkermansia muciniphila*, *Dorea formicigenerans*, and *Bacteroides caccae*.
• Genes encoding glucose metabolism enzymes were located in SV-associated regions.

Conclusions:

• Uncovered a novel layer of gut microbiome genomic heterogeneity impacting ICI treatment prognosis.
• Demonstrated the correlation between microbial SVs and host outcomes in cancer immunotherapy.
• Advanced understanding of the complex interplay between the gut microbiota and tumor immunotherapy.