The FDA approves Roche’s Tecentriq plus chemotherapy for stage III dMMR colon cancer after Phase III ATOMIC results showed a 50% lower risk of recurrence or death.
Written By: Umesh Hanumante,
M.Pharm (Reg. Affairs)
Reviewed By: Pharmacally Editorial Team
The US Food and Drug Administration (FDA) has approved Roche’s Tecentriq (atezolizumab) and Tecentriq Hybreza (atezolizumab and hyaluronidase-tqjs) in combination with fluoropyrimidine and oxaliplatin-based chemotherapy for the adjuvant treatment of stage III deficient mismatch repair (dMMR) colon cancer. The decision establishes the first approved immunotherapy-based adjuvant regimen for this patient population and expands Tecentriq’s US indications to 12.
Phase III ATOMIC Trial Demonstrated Improved Disease-Free Survival
The approval is based on the Phase III ATOMIC trial (A021502; NCT02912559), which evaluated atezolizumab alongside modified FOLFOX6 (mFOLFOX6), a chemotherapy regimen comprising folinic acid, fluorouracil and oxaliplatin.
The randomized, open-label study enrolled 712 patients with surgically resected stage III dMMR colon cancer. Participants received either mFOLFOX6 alone for six months or mFOLFOX6 plus atezolizumab for six months, followed by atezolizumab monotherapy for another six months.
At 36 months, disease-free survival (DFS) was 86% with atezolizumab plus chemotherapy, compared with 76% with chemotherapy alone. Adding atezolizumab reduced the risk of disease recurrence or death by 50%.
The primary endpoint was DFS, which measures the time patients remain alive without cancer recurrence or another qualifying disease event. The trial’s findings were published in The New England Journal of Medicine.
Roche reported that the regimen’s safety profile was consistent with the previously established safety profiles of atezolizumab and mFOLFOX6.
Targeting the Biology of dMMR Colon Cancer
DNA mismatch repair deficiency prevents cells from correcting certain DNA replication errors, allowing mutations to accumulate. These tumours frequently exhibit high microsatellite instability (MSI-H), a characteristic associated with increased tumour mutational burden and potential sensitivity to immune checkpoint inhibitors.
Atezolizumab is a monoclonal antibody that blocks programmed death-ligand 1 (PD-L1), preventing its interaction with PD-1 and B7.1 receptors. This can restore T-cell activity against cancer cells.
Colon cancer remains a major global health burden, with more than one million diagnoses annually. Nearly one-quarter of cases are diagnosed at stage III, when cancer has spread to nearby lymph nodes but has not reached distant sites. Despite surgery and chemotherapy, approximately 30% of patients with stage III colon cancer experience recurrence within five years.
Around 15% of colon cancers have dMMR or MSI-H characteristics, making this molecular subgroup an important target for immunotherapy-based treatment strategies.
Implications for Adjuvant Treatment
Frank A. Sinicrope, MD, the ATOMIC trial’s US principal investigator and a professor of oncology at Mayo Clinic, highlighted the significance of tailoring postoperative treatment to mismatch repair status. Historically, adjuvant treatment for stage III colon cancer has not differed substantially according to this biomarker.
The ATOMIC results support a biomarker-directed approach that combines chemotherapy with immune checkpoint inhibition after surgery, with the potential to reduce recurrence risk in patients with dMMR disease.
Roche Plans Further Regulatory Filings
Roche plans to pursue additional regulatory submissions, including an application to the European Medicines Agency, to expand access to the regimen beyond the United States.
The FDA approval marks a significant development in adjuvant treatment for stage III dMMR colon cancer. Longer-term follow-up will help clarify the durability of the disease-free survival benefit and further inform the regimen’s role in clinical practice.
Reference
FDA approves Roche’s Tecentriq in combination with a fluoropyrimidine and oxaliplatin for the adjuvant treatment of a certain type of stage III colon cancer, Roche, 09 October 2026
Combination Chemotherapy with or Without Atezolizumab in Treating Patients with Stage III Colon Cancer and Deficient DNA Mismatch Repair, ClinicalTrials.gov ID NCT02912559
Frank A. Sinicrope et al, Atezolizumab plus FOLFOX for Stage III Mismatch Repair–Deficient Colon Cancer, N Engl J Med 2026;394:1155-1166, https://www.nejm.org/doi/full/10.1056/NEJMoa2507874
About the Writer
Umesh Hanumante (M.Pharm) (LinkedIn) is a pharmacy professional and healthcare writer with a background in Regulatory Affairs, pharmaceutical innovation, and clinical research. He has around two years of industry experience as an Executive PMT at Troikaa Pharmaceuticals Ltd and qualified GPAT 2024. His areas of interest include regulatory compliance, dossier preparation, clinical trials, emerging therapies, and advancements in the global pharmaceutical and healthcare sector.