This study is a prospective, open-label, dual-arm exploratory Phase II clinical trial designed to assess the efficacy and safety of cadonilimab combined with anti-angiogenic agents in patients with dMMR/MSI-H recurrent or metastatic colorectal cancer. Eligible patients are enrolled into two cohorts based on their prior exposure to PD-1/PD-L1 antibody therapy: Cohort A (immune-naive group - patients with no prior PD-1/PD-L1 treatment) and Cohort B (immune rechallenge group - patients who previously received and failed PD-1/PD-L1 therapy). All participants receive combination therapy with cadonilimab and an anti-angiogenic agent, which is selected by the investigator from bevacizumab, regorafenib, or fruquintinib. Treatment continues until the occurrence of intolerable toxicity, disease progression, withdrawal of informed consent, loss to follow-up, death, other conditions deemed by the investigator to warrant discontinuation, or study termination-whichever occurs first. Cadonilimab treatment will not exceed two years. Tumor response is evaluated every six weeks using RECIST v1.1 criteria. Safety is assessed using CTCAE v5.0, and adverse events are recorded from the first dose to 30 days after the end of treatment.
None
Symptomatic brain metastases. A prior history of a primary tumor outside of the colorectal cancer in 3 years Active autoimmune disease or autoimmune disease with potential for recurrence such as, but not limited to: autoimmune hepatitis, interstitial pneumonia, uveitis, enterocolitis, hepatitis, pituitary inflammation, vasculitis, nephritis, hyperthyroidism, hypothyroidism, previous thyroid surgery cannot be included; subjects with vitiligo or complete remission of asthma in childhood and adult who do not require any intervention afterwards can be included; subjects with asthma requiring medical intervention with bronchodilators cannot be included.