# c-TRAK TN

Source: https://onco.cc/trials/c-trak-tn/  
OnCo record `c-trak-tn` (Trial). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

c-TRAK TN, run from the Royal Marsden and the Institute of Cancer Research, was the first trial to use blood tests for tumour DNA to trigger treatment in triple-negative breast cancer. A quarter of patients tested positive within a year, but most of them already had visible metastases on scans, so the test came too late to prevent relapse with pembrolizumab.

## Summary

c-TRAK TN (NCT03145961) registered 208 patients between January 2018 and December 2019 with early triple-negative breast cancer and residual disease after neoadjuvant chemotherapy or stage II to III disease treated with adjuvant chemotherapy; 185 had tumour sequencing, 171 (92.4 percent) had trackable mutations and 161 entered digital PCR ctDNA surveillance every three months for 12 months (18 if samples were missed during the pandemic). ctDNA-positive patients were randomised 2 to 1 to intervention (staging scans, then pembrolizumab for a year if free of recurrence) or blinded observation; a September 2020 amendment closed the observation group. ctDNA was detected in 27.3 percent by 12 months (44 of 161; 95 percent confidence interval 20.6 to 34.9) and seven patients relapsed without prior ctDNA detection. Of 32 patients allocated to intervention, 72 percent (23) already had metastases on staging and four declined pembrolizumab; of the five who started it, none achieved sustained ctDNA clearance, so the second co-primary endpoint was not met. The trial's lesson, that ctDNA surveillance must start earlier and use more sensitive or frequent assays before it can steer adjuvant treatment, shaped the design of the ctDNA-triggered trials now recruiting.

## Fields

- Kind: Trial
- Status: completed
- Last checked: 2026-09-24
- Also known as: c-TRAK-TN; cTRAK TN
- Registry id: NCT03145961
- Phase: 2
- Setting: Moderate and high-risk early triple-negative breast cancer after neoadjuvant or adjuvant chemotherapy: three-monthly ctDNA mutation tracking for 12 months, with ctDNA-positive patients randomised 2 to 1 to pembrolizumab or observation, 17 UK hospitals
- Sponsor: Institute of Cancer Research, United Kingdom, with the Royal Marsden NIHR Biomedical Research Centre and Merck
- Enrolled: 208
- Result: ctDNA detected in 27.3% by 12 months; 72% of ctDNA-positive patients had metastases on staging; 0 of 5 patients on pembrolizumab cleared ctDNA.
- Outcomes: ctDNA detection by 12 months: Patients under ctDNA surveillance 27.3%; Sustained ctDNA clearance on pembrolizumab: Pembrolizumab 0%
- Replication: BRE12-158 (US) also found post-surgical ctDNA prognostic.

## Notes

- UK sites (registry, 17): Royal Marsden Hospital Chelsea and Sutton, Royal Bournemouth Hospital, Velindre Cancer Centre Cardiff, Western General Hospital Edinburgh, Beatson West of Scotland Cancer Centre Glasgow, Guy's Hospital, Charing Cross Hospital, St Bartholomew's Hospital, University College London Hospitals, Maidstone Hospital, the Christie Manchester, Clatterbridge Cancer Centre, Nottingham University Hospitals, Churchill Hospital Oxford, Weston Park Hospital Sheffield, Royal Cornwall Hospital Truro.

## Sources

- ClinicalTrials.gov NCT03145961: https://clinicaltrials.gov/study/NCT03145961
- Turner et al., Annals of Oncology 2023: results of the c-TRAK TN trial: https://doi.org/10.1016/j.annonc.2022.11.005

## Connected records

- cancers: [Early triple-negative breast cancer](https://onco.cc/cancers/tnbc-early/), [Triple-negative breast cancer (TNBC)](https://onco.cc/cancers/tnbc/)
- technologies: [Immune checkpoint inhibitors](https://onco.cc/technologies/checkpoint-inhibitor/), [MRD / molecular residual disease testing](https://onco.cc/technologies/mrd-testing/)
- drugs: [Pembrolizumab](https://onco.cc/drugs/pembrolizumab/)
- companies: [Merck & Co. (MSD)](https://onco.cc/companies/merck/)
- institutions: [Cancer Research UK](https://onco.cc/institutions/cruk/), [The Royal Marsden](https://onco.cc/institutions/royal-marsden/)
- terms: [Circulating tumour DNA (ctDNA)](https://onco.cc/terms/ctdna/), [Residual cancer burden (RCB)](https://onco.cc/terms/rcb/), [Residual disease after neoadjuvant therapy in triple-negative breast cancer: the decision point](https://onco.cc/terms/tnbc-residual-disease-decision/), [Triple-negative breast cancer trials open today (registry snapshot and UK sites)](https://onco.cc/terms/tnbc-trials-open-today/)
- trials: [BRE12-158 (Hoosier Oncology Group)](https://onco.cc/trials/bre12-158/), [Efficacy and Safety Comparison of Niraparib to Placebo in Participants With Human Epidermal Growth Factor 2 Negative (HER2-) Breast Cancer Susceptibility Gene Mutation (BRCAmut) or Triple-Negative Breast Cancer (TNBC) With Molecular Disease](https://onco.cc/trials/nct04915755/), [KEYNOTE-522](https://onco.cc/trials/keynote-522/)

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