# IMblaze370

Source: https://onco.cc/trials/imblaze370/  
OnCo record `imblaze370` (Trial). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

The trial that tried to make immunotherapy work in ordinary bowel cancer by adding a MEK inhibitor. It failed outright.

## Summary

IMblaze370 randomised 363 patients 2:1:1 to atezolizumab with cobimetinib, atezolizumab alone, or regorafenib, after progression on at least two previous chemotherapy regimens. Median overall survival was 8.87 months with the combination, 7.10 months with atezolizumab alone and 8.51 months with regorafenib; the hazard ratio was 1.00 (95% CI 0.73 to 1.38, p=0.99) for the combination against regorafenib. Grade 3 to 4 adverse events affected 61 percent of the combination group. The preclinical rationale, that MEK inhibition raises MHC class I expression and drives T cells into tumours, did not translate. IMblaze370 is the reference failure for checkpoint inhibition in microsatellite-stable colorectal cancer and the reason later attempts focus on Fc-enhanced CTLA-4 blockade, on excluding patients with liver metastases, or on combining with targeted therapy.

## Fields

- Kind: Trial
- Status: negative
- Last checked: 2026-09-24
- Also known as: COTEZO
- Registry id: NCT02788279
- Phase: 3
- Setting: Previously treated metastatic colorectal adenocarcinoma, mostly microsatellite-stable: atezolizumab with cobimetinib, or atezolizumab alone, against regorafenib
- Sponsor: Hoffmann-La Roche
- Enrolled: 363
- Result: Median overall survival 8.87 months with atezolizumab and cobimetinib against 8.51 months with regorafenib (hazard ratio 1.00).
- Outcomes: Overall survival: Atezolizumab and cobimetinib 8.87 months vs Atezolizumab 7.1 months vs Regorafenib 8.51 months, HR 1

## Sources

- ClinicalTrials.gov NCT02788279: https://clinicaltrials.gov/study/NCT02788279
- IMblaze370: atezolizumab with or without cobimetinib versus regorafenib in previously treated metastatic colorectal cancer (Lancet Oncology 2019): https://doi.org/10.1016/S1470-2045(19)30027-0

## Connected records

- cancers: [Colorectal cancer](https://onco.cc/cancers/colorectal/)
- technologies: [Immune checkpoint inhibitors](https://onco.cc/technologies/checkpoint-inhibitor/), [Small-molecule kinase inhibitors](https://onco.cc/technologies/kinase-inhibitors/)
- targets: [MEK1/2](https://onco.cc/targets/mek/), [PD-1](https://onco.cc/targets/pd1/)
- drugs: [Atezolizumab](https://onco.cc/drugs/atezolizumab/), [Cobimetinib](https://onco.cc/drugs/cobimetinib/), [Regorafenib](https://onco.cc/drugs/regorafenib/)
- companies: [Roche / Genentech](https://onco.cc/companies/roche-genentech/)
- terms: [Colorectal cancer: the failed and stopped programmes, and why](https://onco.cc/terms/colorectal-failed-programmes/), [Hot vs cold tumours](https://onco.cc/terms/cold-vs-hot/), [Microsatellite instability (MSI-H) / mismatch repair deficiency (dMMR)](https://onco.cc/terms/msi/)
- trials: [CheckMate 142](https://onco.cc/trials/checkmate-142/)

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