Phase II Study of Trastuzumab Rezetecan or in Combination With Adebrelimab in HER2-Expressing Locally Advanced or Metastatic Urothelial Carcinoma (la/mUC)

Age ≥ 18 years;

Histologically or cytologically confirmed HER2-expressing locally advanced unresectable (e.g., T4b, or N2-3) or metastatic urothelial carcinoma (la/mUC), including bladder, ureter, renal pelvis, and urethra. HER2 expression is defined as immunohistochemical (IHC) staining results of 1+ to 3+, and must be confirmed by the pathology department of Sun Yat-sen University Cancer Center according to ASCO/CAP guidelines.

Cohort 1: Patients who have received at least one prior systemic therapy, or relapsed/progressed within 12 months after the last treatment, or who could not tolerate treatment due to adverse events (AEs). Cohort 2: Patients who have not received prior systemic therapy or relapsed/progressed more than 12 months after neoadjuvant/adjuvant therapy, or those who could not tolerate treatment due to AEs. Cohort 3: Patients who have previously received platinum-based chemotherapy (including cisplatin, carboplatin, etc.), immunotherapy (including PD-1, PD-L1 inhibitors), and Disitamab Vedotin ;

At least one measurable target lesion according to RECIST 1.1 criteria;