Atezolizumab Approved as Adjuvant Therapy for Stage III dMMR Colon Cancer
The FDA approved intravenous atezolizumab with a fluoropyrimidine and oxaliplatin for adjuvant treatment of stage III mismatch repair-deficient colon cancer in patients aged 2 and older. A subcutaneous form was also approved for patients 12 and older who weigh at least 88 pounds. In the supporting trial, adding atezolizumab to standard adjuvant chemotherapy reduced the risk of recurrence or death by 50%, with 3-year disease-free survival of 86% versus 76%, though grade 3 or higher adverse events were more common.
The FDA cleared intravenous atezolizumab alongside a fluoropyrimidine and oxaliplatin for adjuvant use in stage III dMMR colon cancer from age 2. A subcutaneous version combining atezolizumab with hyaluronidase was also authorized for patients 12 and older weighing at least 88 pounds.
The supporting ATOMIC/ML39057 trial randomized 711 patients. Adding the PD-L1 inhibitor to chemotherapy lowered recurrence or death risk by half; three-year disease-free survival was 86% versus 76%. Grade 3 or higher side effects occurred in 71.7% versus 62.1%.
This approval may give some patients with stage III dMMR colon cancer a new adjuvant option, potentially lowering recurrence risk. Because it includes children as young as 2 and a subcutaneous form for older patients, families and clinicians could have more flexibility. It may also increase demand for mismatch repair testing and immunotherapy monitoring, affecting oncology clinics and payers.