Gut bacterial markers may be able to predict recurrence in patients with high-risk melanoma receiving adjuvant immune checkpoint inhibition, according to study findings published in Cell.
“Our study identified for the first time gut bacterial types that can serve as markers of increased recurrence risk in these specific patients, which will help tailor treatment,” said study senior author Jiyoung Ahn, PhD, Professor in the Department of Population Health at NYU Grossman School of Medicine and Associate Director of Population Research at Perlmutter Cancer Center.
Study Methods
Researchers explored whether pretreatment gut microbiome features impact recurrence in patients with melanoma receiving immune checkpoint inhibition.
“Past studies have struggled because the gut bacteria that predict treatment success seemed to change from one region to another,” said Dr. Ahn. “Our study provides a new method that overcomes this barrier, showing that these markers are indeed generalizable if we account for the person’s underlying microbiome.”
The researchers analyzed stool samples from 674 patients who were enrolled in the phase III CheckMate 915 trial, which included patients with resected, high-risk, stage IIIB–IV melanoma and investigated treatment with adjuvant nivolumab plus ipilimumab or nivolumab alone. They conducted region-specific and cross-region meta-analyses of gut microbiome composition.
Key Findings
Researchers found that pretreatment taxa, including Eubacterium, Ruminococcus, Firmicutes, and Clostridium, were associated with melanoma recurrence.
Prediction was strongest when the validation cohort showed profiles of gut microbiome similar to those in the discovery cohort, with areas under the curve for recurrence prediction ranging from 0.78 to 0.94 across regions in individuals with low Jensen-Shannon divergence figures (≤ 0.11).
The composition of the gut microbiome was mostly stable from pretreatment to posttreatment.
The study authors suggested that gut bacteria could serve as clinically actionable biomarkers to guide personalized therapy in patients with high-risk melanoma.
“This means that a single pretreatment microbiome test could provide a reliable forecast of a patient's risk,” said study author Richard B. Hayes, DDS, PhD, MPH, Professor in the Department of Population Health, NYU Grossman School of Medicine. “The next step is to validate this matching approach in other cancers and to build the diverse databases needed to make this approach clinically feasible. In the future, we envision analyzing a patient’s microbiome before treatment, comparing it to a global database, and providing a reliable prognosis that guides therapy from the start.”
DISCLOSURES: Funding for the study was provided by National Institutes of Health grants. For full disclosures of the study authors, visit cell.com.
