FDA Approves Adjuvant Atezolizumab for Certain Colon Cancers

The FDA on Thursday approved intravenous atezolizumab (Tecentriq) in combination with a fluoropyrimidine and oxaliplatin for the adjuvant treatment of stage III mismatch repair-deficient (dMMR) colon cancer in patients 2 years and up.

The agency also approved the subcutaneous form of the PD-L1 inhibitor (atezolizumab plus hyaluronidase [Tecentriq Hybreza]) for the indication in patients 12 years and older who weigh at least 88 lb.

In the randomized trial supporting these approvals, the addition of atezolizumab to standard adjuvant chemotherapy reduced the risk of disease recurrence or death by 50%.

“Until now, the adjuvant standard of care for stage III colon cancer has not differed based on mismatch repair status,” said Frank Sinicrope, MD, of the Mayo Clinic in Rochester, Minnesota, who was a principal investigator for the trial, in a press release from drugmaker Genentech.

“This milestone represents an important therapeutic advance that leverages immunotherapy to target the specific biology of dMMR stage III colon cancer after surgical resection,” he noted. “By reducing the risk of disease recurrence or death by 50%, atezolizumab plus chemotherapy is a practice-changing regimen that can improve clinical outcomes of this group of patients living with colon cancer, one of the most common cancers and a leading cause of cancer-related death.”

Efficacy was evaluated in ATOMIC/ML39057, a multicenter, open-label trial, which included 711 patients with stage III dMMR colon cancer who were randomized to receive either atezolizumab in combination with oxaliplatin, leucovorin, and fluorouracil for 12 cycles followed by atezolizumab monotherapy for 6 months, or the chemotherapy regimen alone for 12 cycles.

The 3-year disease-free survival rate was 86% with the addition of atezolizumab compared with 76% for those who received chemotherapy alone (HR 0.50, 95% CI 0.35-0.73, P<0.0001).

An analysis of patients with dMMR cancer confirmed by central laboratory review yielded an HR of 0.53 (95% CI 0.36-0.79, P=0.0007).

Grade ≥3 adverse events occurred more often in the atezolizumab arm (71.7% vs 62.1%), but the safety profile of atezolizumab plus chemotherapy was consistent with the drugs’ known effects.

The prescribing information includes warnings and precautions for immune-mediated adverse reactions, infusion-related reactions, complications of allogeneic hematopoietic stem-cell transplantation, and embryo-fetal toxicity.