Dr Sinicrope on the FDA Approval of Atezolizumab Plus Chemo for Colon Cancer

“The addition of atezolizumab to standard fluoropyrimidine and oxaliplatin chemotherapy resulted in a 50% reduction in disease recurrence and death compared [with] chemotherapy alone.”

Frank A. Sinicrope, MD, a professor of medicine and professor of oncology, a consultant in the Division of Medical Oncology in the Department of Oncology, and a consultant in the Division of Gastroenterology and Hepatology in the Department of Internal Medicine at Mayo Clinic in Rochester, Minnesota, discussed the significance of the FDA approval of atezolizumab (Tecentriq) plus chemotherapy for patients with stage III mismatch repair–deficient (dMMR) colon cancer.

On October 8, 2026, the FDA approved atezolizumab in combination with a fluoropyrimidine and oxaliplatin for the adjuvant treatment of adult and pediatric patients 2 years of age and older with stage III dMMR colon cancer; subcutaneous atezolizumab and hyaluronidase-tqjs (Tecentriq Hybreza) with the same chemotherapy was approved for patients 12 years of age and older weighing at least 40 kg. The regulatory decision was based on data from the phase 3 ATOMIC trial (NCT02912559), in which investigators randomly assigned patients with completely resected, dMMR stage III colon cancer 1:1 to receive atezolizumab plus modified FOLFOX6 (mFOLFOX6; leucovorin calcium, fluorouracil, and oxaliplatin) or mFOLFOX6 alone. Treatment with the atezolizumab regimen led to a statistically significant improvement in disease-free survival (DFS; HR, 0.50; 95% CI, 0.35-0.73; P = .0001), with a 3-year DFS rate of 86.3% (95% CI, 81.8%-89.8%) vs 76.2% (95% CI, 70.9%-80.6%) with chemotherapy alone; the median DFS was not reached in either arm. Overall survival outcomes did not differ significantly between these respective arms (5-year rates, 89.7% vs 87.9%; HR, 0.90; 95% CI, 0.55-1.47; P = .68).

This regimen has been incorporated into current guidelines, but the FDA approval provides regulatory endorsement, Sinicrope said. Because the FDA carefully evaluates the benefit-to-risk profile, the approval represents an important assessment, and it focuses on a defined patient population while providing prescribing information that guides clinical use, he noted. The approval also has the potential to improve patient access and facilitate reimbursement worldwide, according to Sinicrope.

The addition of atezolizumab to standard chemotherapy resulted in a 50% reduction in disease recurrence and death compared with chemotherapy alone, Sinicrope said. This benefit with the atezolizumab-based regimen was seen across all patient subgroups examined, he added.