Roche announced on October 9, 2026 that the US Food and Drug Administration has approved Tecentriq (atezolizumab) in combination with fluoropyrimidine and oxaliplatin for adjuvant treatment of stage III colon cancer with deficient DNA mismatch repair. The approval is based on the randomized phase III ATOMIC trial, which enrolled 712 patients after complete tumor removal: one group received six months of standard chemotherapy alone, the other received the same chemotherapy plus atezolizumab followed by atezolizumab monotherapy for a total of twelve months.
After a median follow-up of 40.9 months, researchers compared disease-free survival at three years between both groups. Specifically, 86.3% of patients receiving the combination remained disease-free, compared to 76.2% receiving chemotherapy alone. According to the Alliance, this reduced the risk of recurrence or death by 50%. Study principal investigator Frank A. Sinicrope explained that the adjuvant treatment standard for stage III colon cancer had not previously differed based on mismatch repair status. Atezolizumab binds to PD-L1, preventing its interaction with PD-1 and allowing cytotoxic T cells to attack tumor cells.
The approval affects tumors with dMMR, a disorder of cellular DNA repair. dMMR or MSI-H tumors occur in approximately 15% of colon cancer patients and indicate a higher mutation rate. Worldwide, over one million people are diagnosed with colon cancer annually, nearly 25% in stage III. Despite surgery and chemotherapy, nearly 30% of these patients experience recurrence within five years. The combination is approved for adults and pediatric patients from age two years. The subcutaneous variant Tecentriq Hybreza is approved from age twelve and minimum 40 kilograms body weight. In the ATOMIC trial itself, patients from age twelve were eligible; the studied population comprised 711 adults and one pediatric participant. Sinicrope recommended that every newly diagnosed colon cancer patient be tested for MMR status to detect Lynch syndrome and assess potential benefit from immunotherapy.
How solid are the results
The presented data come from a pre-planned interim analysis with data cutoff February 4, 2025. Study completion is estimated for December 2026. The study authors note that the reported confidence intervals were not adjusted for multiple testing and should not be read as a separate hypothesis test. The study was also open-label, without blinding of patients or physicians. For overall survival, a secondary endpoint, no statistically significant difference between groups was found. Grade 3 or higher adverse events occurred in 84.1% of evaluable patients receiving the combination, compared to 71.9% with chemotherapy. This included fatigue in 10.1% with the combination and 3.3% with chemotherapy. About half of patients in the combination arm discontinued the planned twelve-month treatment early, most due to withdrawal or adverse events. According to study authors, discontinuations due to withdrawal or adverse events were similar during the first six months; higher rates occurred during subsequent atezolizumab monotherapy. The study was funded in part by the National Cancer Institute and Genentech, part of the Roche Group.
In context
For Roche, this represents the twelfth indication for Tecentriq in the United States. As monotherapy, the drug was previously approved for adjuvant treatment after surgery and platinum-based chemotherapy in adults with non-small cell lung cancer stage II to IIIA based on PD-L1 expression. The Alliance calls the colon cancer result the first demonstrated benefit of adjuvant immunotherapy for early-stage dMMR colon cancer. Within global colon cancer diagnoses, the approval affects a subset: approximately 25% of cases are stage III and about 15% of colon cancer patients have dMMR or MSI-H tumors.
Roche stated it is pursuing additional regulatory approvals, including with the European Medicines Agency, to make the therapy accessible to patients with dMMR colon cancer worldwide. The latest NCCN guidelines have already incorporated the ATOMIC results and extend them to patients with stage II colon cancer of type T4bN0.