Chugai files for Tecentriq adjuvant indication in MSI‑High colon cancer

Regulatory filing

Chugai submitted an application to Japan’s Ministry of Health, Labour and Welfare seeking an additional indication for atezolizumab (Tecentriq) as adjuvant treatment for adults and pediatric patients with microsatellite instability‑high (MSI‑High) colon cancer.

ATOMIC trial results

The filing is based on data from the investigator‑initiated global Phase III ATOMIC (Alliance A021502) trial in pathological Stage III deficient mismatch repair (dMMR) colon cancer after curative resection. For the primary endpoint of disease‑free survival, three‑year DFS was 86.3% (95% CI: 81.8–89.8) in the Tecentriq combination arm versus 76.2% (95% CI: 70.9–80.6) in the mFOLFOX6 arm; the combination reduced the risk of disease recurrence or death (stratified hazard ratio 0.50, 95% CI: 0.35–0.73; p<0.001).

Trial design and regulatory timeline

ATOMIC randomized patients to six months of standard adjuvant mFOLFOX6 versus six months of mFOLFOX6 plus Tecentriq followed by six months of Tecentriq monotherapy (12 months total). The FDA has granted Priority Review for the indication with an anticipated decision by 9 October 2026.

Safety

The most common adverse events in the Tecentriq combination arm were hepatic dysfunction (43.9%), skin disorders (33.8%) and hypothyroidism (18.8%); no new safety signals were identified and the safety profile was consistent with the known information for Tecentriq.