FRIDAY, April 3, 2026 (HealthDay News) -- For patients with stage III mismatch repair-deficient (dMMR) colon cancer, the addition of the anti-programmed death ligand 1 agent atezolizumab to a modified regimen of fluorouracil, oxaliplatin, and leucovorin (mFOLFOX6) is associated with significantly improved disease-free survival, according to a study published in the March 26 issue of the New England Journal of Medicine.
Frank A. Sinicrope, M.D., from the Mayo Clinic in Rochester, Minnesota, and colleagues randomly assigned patients with resected stage III dMMR tumors to receive either adjuvant atezolizumab plus mFOLFOX6 for six months, with atezolizumab continued as monotherapy for six months, or mFOLFOX6 alone for six months (355 and 357 patients, respectively).
The researchers found that the three-year disease-free survival was 86.3 and 76.2 percent in the atezolizumab-mFOLFOX6 and the mFOLFOX6-alone groups, respectively, at a median follow-up of 40.9 months (hazard ratio for disease recurrence or death, 0.50). Adverse events of grade 3 or 4 occurred in 84.1 and 71.9 percent of patients who received atezolizumab plus mFOLFOX6 or mFOLFOX6 alone, respectively.
"Our findings highlight why every patient diagnosed with colon cancer should have MMR testing," Sinicrope said in a statement. "This testing helps identify Lynch syndrome and also shows whether a patient may benefit from immunotherapy."
Several authors disclosed ties to biopharmaceutical companies, including Genentech, a member of the Roche group, which partially funded the study.