Assessing disease progression in metastatic colorectal cancer patients using liquid biopsy: a clinical study

Liquid biopsy has become a useful tool for targeted cancer treatment selection. It also has immense potential as a monitoring tool for the emergence of treatment resistance. 

To advance this potential, Canexia Health is collaborating with Exactis Innovation on a clinical study to monitor plasma circulating tumor DNA (ctDNA) in metastatic colorectal cancer patients using Canexia’s Follow It® assay to detect changes in mutations and disease progression. Exactis Innovation is a Canadian National Centre of Excellence in Personalized Medicine comprising a network of 16 oncology centers bringing together public and private partners focusing on precision oncology.

Study objectives included:

• Using a retrospective collection of 55 metastatic colorectal cancer patients enrolled on a clinical trial to determine if longitudinal plasma ctDNA mutation monitoring can aid in predicting clinical progression prior to standard of care CT imaging
• Identifying resistance mechanisms in patients undergoing therapy
• Establishing Canexia’s Follow It assay as a liquid biopsy tool to assess disease progression over time in metastatic colorectal cancer patients

Among the findings:

• PIK3CA mutations are significantly enriched in treatment resistance patients and thus may be a resistance mechanism in this mCRC cohort
• KRAS and PIK3CA are enriched as co-mutated in the resistance population
• RAS wildtype patients often harborTP53 mutations that can be used for ctDNA monitoring
• In the metastatic setting, Follow It detects CRC driver ctDNA mutations in serial longitudinal patient plasma samples within a clinical trial

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