Neoadjuvant Zanidatamab + Tislelizumab + Chemotherapy for Selective Bladder Preservation in HER2-Positive MIBC

Zanidatamab (1,800 mg for patients \<70 kg or 2,400 mg for patients ≥70 kg, administered intravenously every 3 weeks) for 4 cycles is given as part of the neoadjuvant regimen. After completion of neoadjuvant therapy, disease status is reassessed. Patients achieving a clinical complete response (cCR) may continue zanidatamab every 3 weeks for 2-4 cycles as part of bladder-preserving treatment; those without cCR may receive radiotherapy or partial cystectomy followed by zanidatamab every 3 weeks for 2-4 cycles, or undergo radical cystectomy without further zanidatamab treatment.

Tislelizumab (200 mg administered intravenously every 3 weeks) is administered for 4 cycles as neoadjuvant therapy. After completion of 4 cycles, disease status is reassessed. Patients achieving a clinical complete response (cCR) may proceed with selective bladder preservation and continue tislelizumab every 3 weeks for 12 cycles; those without cCR may receive radiotherapy or partial cystectomy followed by tislelizumab every 3 weeks for 12 cycles, or undergo radical cystectomy with adjuvant tislelizumab every 3 weeks for 12 cycles.

Cisplatin (70 mg/m² administered intravenously every 3 weeks ) for 4 cycles is included in the neoadjuvant chemotherapy regimen for eligible cisplatin-based chemotherapy.

Gemcitabine (1,000 mg/m² administered intravenously every 3 weeks) for 4 cycles is given as part of the neoadjuvant chemotherapy regimen for eligible cisplatin-based chemotherapy.

Nab-paclitaxel (125 mg/m² administered intravenously every 3 weeks) for 4 cycles is given as part of the neoadjuvant chemotherapy regimen for ineligible or refused cisplatin-based chemotherapy.