This is a phase Ib/II, open-label, multicenter clinical study to evaluate the safety, tolerability, efficacy, pharmacokinetics and immunogenicity of 9MW2821 combined with Toripalimab injection in subjects with local advanced or metastatic urothelial cancer.

Inclusion Criteria:

• Sign and date the informed consent form e approved by independent ethics committe.
• Male or female subjects aged 18 to 80 years (including 18 and 80 years).
• ECOG status of 0 or 1.
• Histologically or cytologically confirmed local advanced or metastatic urothelial cancer
• Subjects have received at least 1 line advanced standard therapy or were not treated before
• Subjects must submit tumor tissues for test
• Life expectancy of ≥ 12 weeks.
• Subjects must have measurable lesions according to RECIST (version 1.1).
• Adequate organ functions
• Sexually active fertile subjects, and their partners, must agree to use methods of contraception during the study and at least 6 months after termination of study therapy.
• Subjects are willing to follow study procedures.

Exclusion Criteria:

• Anti-tumor treatment such as chemotherapy and radiotherapy within 21 days prior to the first dose of study drug.
• Major surgery within 28 days prior to first dose of study drug.
• PD-1/PD-L1/PD-L2 inhibitors used in the previous treatment for La/m UC.
• Previous treatment with ADCs conjugated with MMAE payload.
• Clinical significantly toxicity Grade ≥ 2 (except alopecia and pigmentation) related to previous treatment.
• Peripheral neuropathy Grade ≥ 2.
• Poorly controlled blood sugar.
• Increased risks of corneal disease assessed by the investigator prior to the first dose of study drug.
• Documented history of clinically significant cardiac or cerebrovascular diseases within 6 months prior to the first dose of study drug.
• Active infections, such as uncontrolled HBV/HCV/HIV/TB infection, etc.
• Other serious or uncontrolled diseases, such as serious interstitial pneumonia/asthma, serious thromboembolic events, etc.
• Poorly controlled central nervous system metastases.
• Organ transplantation or allogeneic hematopoietic stem cell transplantation in the past.
• History of drug abuse or mental illness.
• Known allergic sensitivity to any of the ingredients of the study drug.
• Any P-glycoprotein (P-gp) inducers/inhibitors or potent CYP3A4 inducers/inhibitors within 14 days prior to the first dose of study drug.
• History of autoimmune disease requiring systemic treatment within 2 years before the first dose.
• Any live vaccines within 4 weeks before first dose of study drug or during the study.
• Use of any investigational drug or medical instruments within 28 days prior to the first dose of study drug.
• History of another malignancy within 3 years before the first dose of study drug. Subjects with curable malignancies are allowed.
• Other conditions unsuitable into the study.