This is a prospective, open-label, single-arm exploratory clinical study evaluating the efficacy and safety of disitamab vedotin (RC48) plus toripalimab with cetirizine and mecobalamin in patients with locally advanced unresectable or metastatic bladder cancer who have not received prior systemic therapy for advanced disease.
Disitamab vedotin is a HER2-targeted antibody-drug conjugate, and toripalimab is a PD-1 immune checkpoint inhibitor. Although antibody-drug conjugates have shown antitumor activity in urothelial cancer, treatment-related peripheral neuropathy may affect patients' quality of life and the ability to continue treatment. In this study, cetirizine and mecobalamin are incorporated as a supportive and preventive strategy to explore whether they may help reduce or delay treatment-related peripheral neuropathy while maintaining antitumor activity.
Approximately 10 to 20 participants will be enrolled. The primary outcomes are objective response rate according to RECIST v1.1 and the incidence of treatment-related Grade 2 or higher peripheral neuropathy. Secondary outcomes include overall safety, disease control rate, progression-free survival, and overall survival. Exploratory analyses will evaluate changes in the tumor immune microenvironment, including CD8-positive T-cell infiltration and activation, and their associations with treatment response and peripheral neuropathy.