Prospective characterisation of a novel circulating tumour-derived DNA methylation assay to monitor tumour burden and response to therapy in metastatic colorectal cancer (CATCHER-1)

Interventions: This is an observational trial of a potential biomarker, with no influence on the patients’ treatment and is therefore non-interventional
1.Colvera and CEA will be taken at the following time points
a.Cohort A (first 5 patients): daily (Mon-Fri) for 1 week prior to starting systemic therapy, and daily (Mon-Fri) during cycle 1 week 1 of systemic therapy. Then every 2 weeks for 12 weeks and every 4 weeks thereafter. An interim analysis will be undertaken to evaluate preliminary results to determine the frequency of testing in subsequent cohorts.
b.Cohort B (next 20 patients): at baseline (prior to commencement of systemic therapy), then frequency of testing is to be determined, likely every 2 weeks for 12 weeks and every 4 weeks thereafter.
c.Cohort C (next 25 patients): at baseline (prior to commencement of systemic therapy), then frequency as determined by the emerging data from the first 2 cohorts, likely every 4 to 6 weeks.
Upon cessation of all anti-cancer therapy (i.e. patients receiving best supportive care only), Colvera and CEA blood testing will become voluntary only up until death for a maximum of 20 years.