This is a prospective, open-label, single-center, single-arm clinical study. Plans to enroll 45 MIBC patients with clinical stage T2-T4aN0M0 and HER2-positive (IHC 1+/2+/3+) status. Treatment Flow: Post maximal Transurethral Resection of Bladder Tumor (TURBT); 2 cycles of Gemcitabine + Cisplatin chemotherapy; 4 cycles of RC48-ADC + Toripalimab targeted therapy; Radiotherapy (60-64 Gy) with concurrent Toripalimab treatment; Continue with 6 cycles of RC48-ADC + Toripalimab after radiotherapy completion; Patients achieving CR will receive maintenance therapy with Toripalimab for 1 year.
Male or female ≥18 years of age;
ECOG Performance Status: 0-1;
Patients must have undergone pathological biopsy and imaging diagnosis, and be judged by the investigator to have muscle-invasive bladder urothelial carcinoma (urothelial carcinoma as the main pathological component >50%);
Clinical stage T2-T4a N0 M0 (CT/MRI ± PET/CT);
Previous treatment with anti-PD-1, anti-PD-L1, or anti-PD-L2 therapy, including during the adjuvant therapy phase;
Known allergy to recombinant humanized anti-PD-1 monoclonal antibody drugs or their components;
Received other anti-tumor therapy (including corticosteroid therapy, immunotherapy) or participated in other clinical studies within 4 weeks before the start of study treatment, or have not recovered from previous toxicity (except for Grade 2 alopecia and Grade 1 neurotoxicity);
Pregnant or lactating women;