# OPUS

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

## TL;DR

The oxaliplatin companion to CRYSTAL. It confirmed that the EGFR antibody only works when KRAS is normal.

## Summary

OPUS randomised 344 patients with EGFR-expressing metastatic colorectal cancer to FOLFOX4 with or without cetuximab. KRAS status was evaluable in 315 of them (93 percent) and 179 (57 percent) were wild-type; 11 of 309 KRAS and BRAF evaluable tumours carried a BRAF mutation, all in the KRAS wild-type group. In KRAS wild-type disease cetuximab improved progression-free survival (hazard ratio 0.567, p=0.0064) and response (odds ratio 2.551, p=0.0027). The trial was too small to judge BRAF. Together with CRYSTAL it made KRAS testing compulsory in 2008 and 2009, the first negative predictive biomarker in solid-tumour oncology.

## Fields

- Kind: Trial
- Status: positive
- Last checked: 2026-09-24
- Registry id: NCT00125034
- Phase: 2
- Setting: First-line EGFR-expressing metastatic colorectal cancer: FOLFOX4 with or without cetuximab, analysed by KRAS and BRAF status
- Sponsor: Merck KGaA
- Enrolled: 344
- Result: In KRAS wild-type disease, progression-free survival hazard ratio 0.567 and response odds ratio 2.551 with cetuximab added.
- Outcomes: Progression-free survival (KRAS wild-type): FOLFOX4 plus cetuximab 0.567 hazard ratio vs FOLFOX4 1 hazard ratio, HR 0.567

## Sources

- ClinicalTrials.gov NCT00125034: https://clinicaltrials.gov/study/NCT00125034
- OPUS: efficacy according to biomarker status of cetuximab plus FOLFOX-4 as first-line treatment (Annals of Oncology 2011): https://doi.org/10.1093/annonc/mdq632

## Connected records

- cancers: [Colorectal cancer](https://onco.cc/cancers/colorectal/)
- technologies: [Cytotoxic chemotherapy](https://onco.cc/technologies/cytotoxic-chemotherapy/), [Monoclonal antibodies](https://onco.cc/technologies/monoclonal-antibody/)
- targets: [BRAF](https://onco.cc/targets/braf/), [EGFR](https://onco.cc/targets/egfr/), [KRAS](https://onco.cc/targets/kras/)
- drugs: [Cetuximab](https://onco.cc/drugs/cetuximab/), [FOLFOX (5-FU, leucovorin, oxaliplatin)](https://onco.cc/drugs/folfox/), [Oxaliplatin](https://onco.cc/drugs/oxaliplatin/)
- companies: [Merck KGaA (EMD Serono)](https://onco.cc/companies/merck-kgaa/)
- trials: [CRYSTAL & FIRE-3](https://onco.cc/trials/crystal-fire3/), [NCIC CO.17](https://onco.cc/trials/co-17/), [PARADIGM](https://onco.cc/trials/paradigm/), [PRIME](https://onco.cc/trials/prime/)
- biomarkers: [RAS wild-type (extended KRAS and NRAS testing)](https://onco.cc/biomarkers/ras-wild-type/)

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