COMMIT: A Randomized Study of mFOLFOX6/Bevacizumab/Atezolizumab or Atezolizumab Alone as First-Line Treatment of Deficient DNA Mismatch Repair Metastatic Colorectal Cancer.

In 30 seconds

COMMIT was a multicentre, open-label, randomised phase III trial comparing first-line atezolizumab alone with mFOLFOX6/bevacizumab plus atezolizumab in patients with dMMR/MSI-H metastatic colorectal cancer. The chemotherapy/bevacizumab-only arm closed early after 20 patients enrolled; 41 patients were assigned to each of the two continuing arms. At a median follow-up of 46 months, combination treatment improved progression-free survival versus atezolizumab alone (HR 0.439 [95% CI, 0.23 to 0.84]; P = .0103). Response and 12-month disease control rates were also higher with the combination, alongside more grade 3 or higher adverse events.

Key findings

• Progression-free survival favoured mFOLFOX6/bevacizumab/atezolizumab over atezolizumab alone (HR, 0.439 [95% CI, 0.23 to 0.84]; P = .0103).
• Objective response rates were 86.1% with combination treatment and 46% with atezolizumab alone.
• Disease control at 12 months was 64.7% versus 32.4%, respectively.
• Grade 3 or higher adverse events of any attribution occurred in 34 combination-arm patients and 18 atezolizumab-arm patients.

Why it matters

The trial provides randomised evidence that adding chemotherapy and bevacizumab to PD-L1 inhibition can improve progression-free survival in first-line dMMR/MSI-H metastatic colorectal cancer. The higher response and disease-control rates may be relevant when considering treatment strategies, while the greater number of severe adverse events underscores the need to weigh disease control against treatment burden.

What to keep in mind

The chemotherapy/bevacizumab-only arm closed after 20 patients, and the comparison continued with 41 patients in each of the two remaining arms. The open-label design and modest sample size limit the breadth of inference.