Efficacy and Safety of Two Bladder-preserving Treatment Durations With Disitamab Vedotin Plus Toripalimab Combination in Her2-expressing Muscle-invasive Bladder Cancer: A Phase II, Open-Label, Randomized Clinical Trial

Inclusion Criteria:

1. Voluntary agreement to participate in the study and provision of signed and dated informed consent form.
2. Male or female, aged ≥ 18 years.
3. Life expectancy of ≥ 18 months.
4. Pathologically and radiologically confirmed diagnosis of muscle-invasive bladder cancer (MIBC), clinical stage cT2-4aN0M0.
5. Ability to provide tumor tissue specimen from the primary site for HER2 testing; HER2 expression of IHC 1+, 2+, or 3+.
6. No prior systemic therapy for bladder cancer.
7. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.
8. Adequate cardiac, bone marrow, hepatic, and renal function (as per the reference ranges of the investigating center).

Exclusion Criteria:

1. History of malignancies other than urothelial carcinoma, with the following exceptions:Patients who have received potentially curative therapy and have no evidence of the disease for 5 years.Adequately treated basal cell or squamous cell carcinoma of the skin, superficial bladder cancer, carcinoma in situ of the cervix, or other in situ carcinomas that have undergone curative resection.
2. Conditions affecting drug absorption, distribution, metabolism, or excretion.
3. Prior allogeneic stem cell or solid organ transplantation.Prior systemic anti-cancer therapy (including Chinese herbal medications with anti-cancer indications).Less than 4 weeks between the completion of prior therapy and the first dose of study treatment, or presence of persistent adverse events from previous treatments that have not recovered to ≤ Grade 1 per CTCAE (excluding alopecia or pigmentation).
4. History or current presence of congenital or acquired immunodeficiency diseases.
5. Active or documented history of autoimmune or inflammatory disorders.