FDA Approves Tecentriq Plus Chemotherapy for Stage 3 dMMR Colon Cancer

The Food and Drug Administration (FDA) approved Tecentriq (atezolizumab) in combination with chemotherapy on Oct. 8 as an adjuvant (after-surgery) treatment for adults and children 2 years and older with stage 3 mismatch repair deficient (dMMR) colon cancer, according to a news release from the agency.

Under the approval, Tecentriq is given with a fluoropyrimidine and oxaliplatin, two types of chemotherapy. The FDA also approved Tecentriq Hybreza (atezolizumab and hyaluronidase-tqjs), a form of Tecentriq given as an injection under the skin, with the same chemotherapy for adults and children 12 years and older who weigh 40 kilograms or more with stage 3 dMMR colon cancer.

What did the ATOMIC trial show in stage 3 dMMR colon cancer?

The approval was based on results from the ATOMIC trial, in which patients who received Tecentriq plus chemotherapy had a 50% lower risk of their cancer returning or death compared with those who received chemotherapy alone.

The trial’s main measure of success was disease-free survival, or the length of time after treatment that patients lived without their cancer coming back, as assessed by the investigators. The median disease-free survival, the point at which half of patients had their cancer return or died, was not reached in either group. That means more than half of patients in each group had not had a recurrence or died when the data were analyzed. The difference between the two groups was unlikely to have come about by chance.

How was the ATOMIC trial in stage 3 dMMR colon cancer designed?

ATOMIC enrolled 711 adults and one pediatric patient with stage 3 dMMR colon cancer. All patients had surgery to fully remove the original tumor, and none had signs of cancer remaining in the lymph nodes or cancer that had spread to other parts of the body.

Patients were split evenly into two groups at random. One group received Tecentriq with mFOLFOX6, a chemotherapy regimen made up of oxaliplatin, leucovorin and fluorouracil, for 12 cycles, followed by six months of Tecentriq monotherapy. The other group received mFOLFOX6 alone for 12 cycles. The trial was open label, meaning patients and their doctors knew which treatment they were receiving.

How is Tecentriq given for stage 3 dMMR colon cancer?

Adults receive Tecentriq through an IV every two, three or four weeks, depending on the dose, alongside chemotherapy for six months. Tecentriq then continues as monotherapy for six months or until the cancer returns or side effects become too severe. Children receive a dose based on their weight on the same schedule.

Tecentriq Hybreza is given as one injection under the skin every three weeks with chemotherapy for six months, followed by six months of Tecentriq Hybreza monotherapy or until the cancer returns or side effects become too severe. A recommended dose has not been set for children under 12 or for patients 12 and older who weigh less than 40 kilograms.

What side effects are associated with Tecentriq in stage 3 dMMR colon cancer?

The prescribing information includes warnings for immune-related side effects, in which the immune system can affect healthy organs and tissues, as well as infusion-related reactions. It also warns of complications in patients who later receive an allogeneic stem cell transplant (a transplant using cells from a donor) and of possible harm to an unborn baby.

What does the Tecentriq approval mean for patients with stage 3 dMMR colon cancer?

Patients with stage 3 dMMR colon cancer who have had surgery now have an FDA-approved option that adds Tecentriq to standard chemotherapy after surgery, with a version available as an injection under the skin for eligible patients.

The FDA reviewed the applications under priority review and through Project Orbis, a program that allows drug applications to be reviewed at the same time by regulators in multiple countries. Reviews by health agencies in Australia, Canada, Israel and Switzerland are ongoing.

Reference

1. “FDA approves atezolizumab in combination with chemotherapy for Stage III mismatch repair deficient colon cancer.” U.S. Food and Drug Administration. Posted: Oct. 8, 2026.

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