Colorectal cancer remains a leading cause of global mortality, yet patients with MSI-H/dMMR colon cancer often see limited benefit from standard chemotherapy, which yields pathological response rates of approximately 7%. By targeting both PD-1 and CTLA-4 pathways, cadonilimab aims to trigger a more robust antitumor immune response than traditional single-target inhibitors. The current trial seeks to determine if this dual blockade can increase major pathological response rates and reduce the risk of postoperative recurrence.

Evidence supporting this approach stems from earlier Phase II data, where cadonilimab monotherapy achieved an 84.6% pathological complete response rate and a 100% major pathological response rate in patients who underwent surgery. While immune checkpoint inhibitors are established in metastatic cases, no such therapy is currently approved for perioperative use in localized MSI-H/dMMR colon cancer. Akeso’s shift into this space reflects a broader effort to position the drug as a foundational therapy across various oncology settings, including lung, gastric, and cervical cancers.