Hong Kong, China, October 10, 2026
Akeso, Inc. has announced that the first patient has been dosed in a Phase 3 clinical trial of cadonilimab, its investigational PD-1/CTLA-4 bispecific antibody, for the perioperative treatment of resectable colon cancer. The study, known as COMPASSION-40/AK104-313, will evaluate cadonilimab as a single-agent immunotherapy in patients with microsatellite instability-high (MSI-H) or mismatch repair-deficient (dMMR) colon cancer. The trial marks an expansion of the candidate’s clinical development into an earlier treatment setting, where therapies administered before and after surgery may help improve long-term outcomes. Developed by Akeso, cadonilimab is designed to simultaneously target two immune checkpoint pathways involved in regulating antitumor immune responses. The company stated that the trial represents the 13th Phase 3 or registrational study of cadonilimab worldwide. The initiation of this study is an important milestone in evaluating immunotherapy for localized colon cancer, a setting where additional treatment options are needed to improve disease control and reduce the risk of recurrence. Cadonilimab remains investigational for this specific perioperative indication, and its potential benefits must be established through further clinical evaluation.
Phase 3 Study Evaluates Perioperative Colon Cancer Treatment
The COMPASSION-40/AK104-313 Phase 3 study is investigating cadonilimab in patients with resectable MSI-H or dMMR colon cancer. Perioperative treatment refers to therapy administered around the time of surgery, including treatment before the operation and after the procedure. The objective is to improve tumor response before surgery and potentially reduce the likelihood of cancer returning afterward. MSI-H and dMMR tumors contain abnormalities in DNA repair mechanisms, which can lead to the accumulation of mutations and the production of tumor-associated antigens that may make cancer cells more recognizable to the immune system. Although these tumors can respond well to immunotherapy, treatment strategies for patients with localized disease continue to be investigated. Conventional perioperative chemotherapy has demonstrated limited pathological response rates in this particular patient population, highlighting an important unmet medical need. The Phase 3 trial will provide an opportunity to assess whether dual immune checkpoint inhibition with cadonilimab can deliver meaningful clinical benefits in resectable colon cancer. The announcement confirms that the first patient has received treatment, but it does not yet report efficacy outcomes from the new study. Future clinical results will be required to establish the therapy’s performance and determine its potential role in treatment.
Cadonilimab Targets PD-1 and CTLA-4 Pathways
Cadonilimab is a bispecific antibody designed to target programmed cell death protein 1 (PD-1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) simultaneously. Both proteins are immune checkpoint regulators that can limit T-cell activity. By blocking these pathways together, cadonilimab is designed to strengthen immune-mediated responses against cancer cells through complementary mechanisms. This approach differs from therapies that inhibit only one checkpoint and is intended to improve antitumor activity. Earlier clinical research provides a scientific rationale for investigating the candidate in MSI-H/dMMR colorectal cancer. In a previously reported Phase 2 study of neoadjuvant cadonilimab, patients who proceeded to surgery achieved a pathological complete response rate of 84.6% and a major pathological response rate of 100%. A pathological complete response means that no residual cancer is detected in the examined surgical tissue, while a major pathological response indicates a substantial reduction in viable tumor cells. These findings were reported at the 2024 European Society for Medical Oncology Immuno-Oncology Congress. However, results from an earlier study do not establish that the same response rates will be achieved in the Phase 3 trial. The larger confirmatory study will be important for evaluating the reproducibility, safety and clinical significance of the earlier findings.
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Akeso Expands Cadonilimab’s Global Oncology Development
The new colon cancer study expands the clinical development of cadonilimab beyond its existing research programs in gastric, lung and cervical cancers. The candidate is already approved in China for certain cervical cancer and gastric or gastroesophageal junction cancer indications. Akeso is evaluating cadonilimab across multiple Phase 3 and registrational studies, reflecting its strategy to investigate dual immune checkpoint inhibition across different cancer types and treatment settings. The COMPASSION-40 study will help determine whether the medicine can provide an effective perioperative immunotherapy option for patients with resectable MSI-H/dMMR colon cancer. Its development will require careful assessment of tumor response, recurrence, survival outcomes and treatment-related adverse events. Longer-term follow-up will also be important to understand whether any early pathological responses translate into durable clinical benefits. The initiation of Phase 3 testing is a development milestone, not proof of efficacy or regulatory approval for this indication. The forthcoming clinical evidence will determine whether cadonilimab can become a meaningful addition to treatment strategies for patients with localized colon cancer.
Source: Akeso press release
