Colorectal Cancer Metastatic dMMR Immuno-Therapy (COMMIT) Study: A Randomized Phase III Study of mFOLFOX6/Bevacizumab Combination Chemotherapy with or without Atezolizumab or Atezolizumab Monotherapy in the First-Line Treatment of Patients with Deficient DNA Mismatch Repair (dMMR) Metastatic Colorectal Cancer


Primary Objective:

  • To determine the efficacy, based on PFS, of mFOLFOX6/bevacizumab plus atezolizumab (combination) and atezolizumab (single agent) as compared to mFOLFOX6/bevacizumab (control).

Secondary Objectives:

  • To compare the overall survival.
  • To compare the objective response rates (ORR) per Response Evaluation Criteria in Solid Tumors (RECIST) 1.1.
  • To determine the safety profiles of the combination of mFOLFOX6/bevacizumab/atezolizumab and atezolizumab monotherapy in patients with mismatch-repair deficient (dMMR) metastatic colorectal cancer (mCRC).
  • To compare the surgical conversion rate.
  • To compare disease control rate (complete response [CR] + partial response [PR] + stable disease [SD]) at 12 months.
  • To determine the duration of response and stable disease. VII. To determine the progression-free survival (PFS) by retrospective central independent scan review.

Study Arms

  • Active Comparator: Arm I (bevacizumab, mFOLFOX6)
  • Experimental: Arm II (atezolizumab)
  • Experimental: Arm III (atezolizumab, bevacizumab, mFOLFOX6)


  • Diagnosis of metastatic adenocarcinoma of colon or rectum without previous chemotherapy or any other systemic therapy for metastatic colorectal cancer
  • Tumor determined to be mismatch-repair deficient (dMMR) by Clinical Laboratory Improvement Act (CLIA)-certified immunohistochemical (IHC) assay with a panel of all four IHC markers, including MLH1, MSH2, PMS2, and MSH6; Note: microsatellite instability high (MSI-H) diagnosed by microsatellite instability (MSI) testing (either Bethesda markers or Pentaplex panel) or by next-generation sequencing (NGS) is not eligible unless dMMR is confirmed by CLIA-certified immunohistochemical (IHC) assay with a panel of all four IHC markers including MLH1, MSH2, PMS2 and MSH6
  • An adequate amount of archived tumor tissue, either from primary colorectal cancer site or metastatic lesions
  • Documentation by positron emission tomography(PET)/computed tomography (CT) scan, CT scan, or magnetic resonance imaging (MRI) that the patient has untreated measurable metastatic disease per RECIST 1.1
  • No immediate need for surgical intervention for the primary tumor or palliative diversion/bypass
  • Absolute neutrophil count (ANC) must be >= 1500/mm^3 (obtained within 28 days prior randomization)
  • Platelet count must be >= 100,000/mm^3 (obtained within 28 days prior randomization)
  • Hemoglobin must be >= 8 g/dL (obtained within 28 days prior randomization)