Longitudinal gut microbiome changes in immune checkpoint blockade-treated advanced melanoma

Area of Science:

• Oncology
• Microbiome Research
• Immunotherapy

Background:

• Immune checkpoint blockade (ICB) therapy shows promise in cancer treatment.
• Optimizing ICB efficacy necessitates understanding the role of the gut microbiome.
• Longitudinal microbiome data is crucial for predicting treatment outcomes.

Purpose of the Study:

• To investigate longitudinal gut microbiome changes in patients undergoing ICB for advanced melanoma.
• To identify microbial signatures associated with progression-free survival (PFS) and overall survival.
• To explore how microbial dynamics vary with ICB regimen, adverse events, and medication use.

Main Methods:

• Longitudinal microbiome profiling of 175 advanced melanoma patients treated with ICB.
• Analysis of species-level genome bins (SGBs) and metabolic pathways.
• Statistical comparison of microbial profiles between patients with PFS ≥12 months and PFS <12 months.
• Correlation analysis of microbial signatures with overall survival and clinical factors.

Main Results:

• Distinct baseline and post-treatment microbial patterns were observed between PFS groups.
• 99 SGBs discriminated between PFS outcomes, with 20 at baseline and 42 post-treatment.
• Five and four SGBs were consistently enriched in patients with longer and shorter PFS, respectively.
• A log ratio of specific SGBs correlated with overall survival.
• Microbial dynamics differed based on ICB type, immune-related adverse events, and medication use.

Conclusions:

• Gut microbiome composition and dynamics are significantly associated with ICB treatment response and survival in melanoma.
• Specific microbial species and their longitudinal changes can serve as predictive biomarkers for ICB efficacy.
• Understanding these host-microbiome-treatment interactions is vital for developing microbiome-targeted therapies to enhance ICB outcomes.