# NCIC CO.17

Source: https://onco.cc/trials/co-17/  
OnCo record `co-17` (Trial). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

The trial that proved an EGFR antibody on its own lengthens life in bowel cancer, and whose stored tumour blocks then proved that only KRAS-normal tumours benefit.

## Summary

CO.17 randomised 572 patients with pretreated EGFR-positive metastatic colorectal cancer to cetuximab with best supportive care or best supportive care alone. Cetuximab improved overall survival (hazard ratio for death 0.77, 95% CI 0.64 to 0.92, p=0.005) and progression-free survival (hazard ratio 0.68, 0.57 to 0.80) while preserving quality-of-life measures. Its lasting importance is the retrospective biomarker analysis of the trial's tumour blocks, published a year later, which found the survival benefit confined to KRAS wild-type tumours and absent, with a trend to harm, in KRAS-mutant ones: the first negative predictive biomarker in solid-tumour oncology and the reason RAS testing became mandatory before any EGFR antibody.

## Fields

- Kind: Trial
- Status: positive
- Last checked: 2026-09-24
- Also known as: CO.17
- Registry id: NCT00079066
- Phase: 3
- Setting: Pretreated EGFR-positive metastatic colorectal cancer with no remaining standard option: cetuximab with best supportive care against best supportive care alone
- Sponsor: NCIC Clinical Trials Group
- Enrolled: 572
- Result: Overall survival hazard ratio 0.77 (95% CI 0.64 to 0.92, p=0.005) against best supportive care alone; benefit confined to KRAS wild-type tumours.
- Outcomes: Overall survival: Cetuximab plus best supportive care 0.77 hazard ratio vs Best supportive care 1 hazard ratio, HR 0.77
- Replication: PRIME extended the same logic prospectively to all of KRAS and NRAS.

## Sources

- ClinicalTrials.gov NCT00079066: https://clinicaltrials.gov/study/NCT00079066
- CO.17: cetuximab for the treatment of colorectal cancer (New England Journal of Medicine 2007): https://doi.org/10.1056/NEJMoa071834

## Connected records

- cancers: [Colorectal cancer](https://onco.cc/cancers/colorectal/)
- technologies: [Monoclonal antibodies](https://onco.cc/technologies/monoclonal-antibody/)
- targets: [EGFR](https://onco.cc/targets/egfr/), [KRAS](https://onco.cc/targets/kras/)
- drugs: [Cetuximab](https://onco.cc/drugs/cetuximab/)
- companies: [Canadian Cancer Trials Group (CCTG)](https://onco.cc/companies/cctg/)
- trials: [CRYSTAL & FIRE-3](https://onco.cc/trials/crystal-fire3/), [OPUS](https://onco.cc/trials/opus/), [PRIME](https://onco.cc/trials/prime/)

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