A multicenter, open, single arm, phase II clinical trial was designed for myometrial invasive bladder cancer to evaluate the efficacy and safety of RC48-ADC combined with gemcitabine in preoperative neoadjuvant treatment of MIBC, and provide high-level clinical evidence for gemcitabine combined with ADC in the treatment of MIBC

Patients with myometrial invasive bladder cancer expressing HER2 and not suitable for cisplatin chemotherapy were treated with vedixizumab (RC48) 2.0mg/kg, once every two weeks, intravenous drip (60-90min); Gemcitabine is 1000mg/m2, once every two weeks. After completing 3 cycles of neoadjuvant combined therapy, imaging evaluation was performed. If the tumor is T0, radical surgery for bladder cancer was performed; Otherwise, perform radical surgery for bladder cancer (total cystectomy+standard/extended lymph node dissection) after completing 1-3 cycles of treatment.

Inclusion Criteria:

1. Subjects voluntarily joined the study, signed the informed consent form, and were able to follow the study and follow-up procedures
2. Age 18-75
3. Suitable and planned for radical cystectomy (including lymph node dissection)
4. Clinical stage T2-T4aN0M0 (CT/MR/PET-CT evaluation)
5. Pathologically, it is urothelial carcinoma, and the patient has HER2 expression and refuses neoadjuvant chemotherapy or physical condition/renal function [glomerular filtration rate (GFR) 30-60mL/min], which is not suitable for neoadjuvant chemotherapy (pathology allows urothelial carcinoma to merge with other variant subtypes, with urothelial carcinoma as the main type)
6. ECOG score 0 or 1
7. There is residual tumor after TURBT (cystoscopy or imaging evidence)
8. The blood test of subjects should meet the following requirements

Exclusion Criteria:

1. Receive live attenuated vaccine within 4 weeks before enrollment or during the study period.
2. Have received systemic chemotherapy and targeted therapy of anti-PD-1, PD-L1 and HER2 in the past 6 months
3. Known allergy to gemcitabine/RC48 and its components
4. Active, known or suspected autoimmune diseases.
5. A history of primary immunodeficiency is known.