Circulating tumor DNA as a predictive biomarker for pathologic response after treatment with neoadjuvant immunotherapy for localized dMMR/MSI-H colorectal cancer.
Pilot analysis demonstrates ctDNA clearance predicts pathologic complete response in localized dMMR/MSI-H CRC, suggesting its use as a biomarker.
Key Points
Pathologic complete response is predicted by ctDNA clearance after neoadjuvant immunotherapy in colorectal cancer.
Detection of baseline ctDNA occurred in 7 of 13 patients, with a median variant allele frequency of 8.5%.
The analysis employed a tumor-agnostic NGS-based ctDNA assay across 49 plasma samples collected serially from 13 patients. PCR was observed in 6 of 6 patients without detectable ctDNA at baseline, compared to only 4 of 7 with detectable ctDNA.