This is a Phase II clinical study aimed at evaluating the safety, tolerability, antitumor efficacy, PK and immunogenicity of AK146D1 monotherapy or combined with AK112 in advanced Urothelial carcinoma.

Inclusion Criteria:

• Be able to understand and voluntarily sign the written informed consent form.
• Age 18-75.
• ECOG PS 0 or 1.
• Expected lifespan ≥3 months.
• Histologically or cytologically documented Urothelial carcinoma.
• At least one measurable lesion according to RECIST v1.1.
• Sufficient organ function.

Exclusion Criteria:

• Having other active malignancies within 3 years.
• Currently participating in another interventional clinical study.
• Presence of active metastases to the central nervous system.
• Prior chemotherapy agent targeting topoisomerase I .
• Receipt of systemic anti-tumor therapy within 4 weeks prior to the first dose.
• Patients with clinically significant cardiovascular or cerebrovascular diseases or risks.
• Patients with active autoimmune diseases requiring systemic treatment within 2 years.
• Receipt of systemic anti-infective therapy within 2 weeks prior to the first dose.
• Previous history of severe hypersensitivity reactions.
• Patients with a history of mental illness and incapacitated or limited capacity.
• Any disease or condition that, in the opinion of the investigator, would compromise patient safety or interfere with study assessments.