FDA approves atezolizumab with chemotherapy for stage III colon cancer

On October 8, 2026, the FDA approved Genentech's atezolizumab (Tecentriq) with chemotherapy as adjuvant treatment for adult and pediatric patients aged 2 and older with stage III dMMR colon cancer. The agency also approved a subcutaneous formulation, atezolizumab and hyaluronidase-tqjs (Tecentriq Hybreza), for patients aged 12 and older weighing at least 40 kg. Based on the phase 3 ATOMIC trial of 712 patients, adding atezolizumab to chemotherapy reduced the hazard of a disease-free survival event by 50% compared to chemotherapy alone, though the combination led to higher rates of grade 3 or higher adverse events.

ATOMIC trial design and efficacy

• ▪Adding atezolizumab to chemotherapy in the ATOMIC/ML39057 trial resulted in a disease-free survival hazard ratio of 0.50, representing a 50% lower hazard of a disease-free survival event than with chemotherapy alone
• ▪ATOMIC/ML39057 trial participants were randomized 1:1 to receive either atezolizumab plus modified FOLFOX6 for 12 cycles followed by 6 months of atezolizumab monotherapy, or modified FOLFOX6 alone for 12 cycles
• ▪The phase 3 ATOMIC/ML39057 trial evaluated 711 adults and 1 pediatric patient with stage III mismatch repair deficient colon cancer who had undergone complete resection of the primary tumor
• ▪In the peer-reviewed ATOMIC/ML39057 trial publication, the 3-year disease-free survival rate was 86.3% with atezolizumab plus modified FOLFOX6 compared to 76.2% with modified FOLFOX6 alone

Safety and adverse events

• ▪The prescribing information for atezolizumab carries warnings for immune-mediated adverse reactions, infusion-related reactions, complications of allogeneic hematopoietic stem cell transplantation, and embryo-fetal toxicity
• ▪Grade 3 or higher adverse events occurred in 84.1% of patients receiving the atezolizumab plus modified FOLFOX6 combination compared to 71.9% of those receiving modified FOLFOX6 alone, with 2 treatment-related deaths in the atezolizumab plus modified FOLFOX6 arm

Recommended intravenous dosing

• ▪The recommended intravenous atezolizumab dose for adults is 840 mg every 2 weeks, 1200 mg every 3 weeks, or 1680 mg every 4 weeks, administered with chemotherapy for 6 months followed by 6 months of monotherapy
• ▪The recommended intravenous atezolizumab dose for pediatric patients is 10 mg/kg up to 840 mg every 2 weeks, or 15 mg/kg up to 1200 mg every 3 weeks

Subcutaneous formulation approval and dosing

• ▪The subcutaneous formulation of atezolizumab and hyaluronidase-tqjs is administered as a single 15 mL injection containing 1875 mg of atezolizumab and 30,000 units of hyaluronidase every 3 weeks
• ▪The FDA approved a subcutaneous formulation, atezolizumab and hyaluronidase-tqjs, for adult and pediatric patients aged 12 years and older weighing at least 40 kg

Debatable claims

• ▪The FDA's approval of atezolizumab for pediatric patients is justified despite the lack of pediatric trial participants
• ▪The disease-free survival benefit of adding atezolizumab to chemotherapy justifies the increased risk of severe adverse events
• ▪The FDA should require overall survival data before approving immunotherapy combinations for stage III colon cancer