Study on Immunotherapy Enhancement Strategies for Muscle-invasive Bladder Cancer
This is a multicenter, prospective, open-label, Phase II, four-arm parallel study evaluating the efficacy and safety of different sensitization strategies combined with disitamab vedotin and toripalimab in patients with HER2-positive muscle-invasive urothelial carcinoma of the bladder (MIBC). Eligible patients with cT2-4aN0M0 HER2-positive urothelial carcinoma of the bladder will receive neoadjuvant disitamab vedotin plus toripalimab in combination with one of four sensitizing agents: sitagliptin, tazemetostat, tafolecimab, or ursodeoxycholic acid. After six cycles of neoadjuvant treatment, patients will undergo comprehensive response assessment, including imaging, cystoscopy, urine cytology, and complete transurethral resection of bladder tumor (cTURBT). Patients who achieve a clinical complete response (cCR) may enter a bladder-preservation treatment pathway, including additional disitamab vedotin plus toripalimab and subsequent toripalimab maintenance therapy. Patients who do not achieve cCR will be considered for salvage radical cystectomy. The primary objective is to evaluate the cCR rate of each treatment strategy. Secondary objectives include bladder-intact disease-free survival, overall survival, bladder preservation rate, safety, quality of life, treatment costs, and exploratory biomarker analyses.
• Voluntarily participate in this study, provide written informed consent, and be able to understand and agree to comply with the study requirements and assessment schedule.
• Age ≥18 years on the date of signing the informed consent form.
• Histologically confirmed and radiologically assessed cT2-T4aN0M0 urothelial carcinoma of the bladder according to the American Joint Committee on Cancer (AJCC) 8th edition TNM staging system. For tumors with mixed histology, urothelial carcinoma must be the predominant component (at least 50%).
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.
• HER2 expression ≥1+ confirmed by immunohistochemistry using a pretreatment tumor specimen tested at a local laboratory.
• Availability of tumor tissue obtained from transurethral resection of bladder tumor (TURBT), together with the corresponding pathology report. Fresh surgical tissue or unstained pathology slides may be submitted.
• Adequate organ function, as determined by the following screening laboratory values obtained within 14 days before enrollment:
• a. For assessment of the following hematologic parameters, participants must not have received growth factor support within 14 days before sample collection: i. Absolute neutrophil count ≥1.5 × 10\^9/L; ii. Platelet count ≥90 × 10\^9/L; iii. Hemoglobin ≥90 g/L. b. International normalized ratio (INR) or activated partial thromboplastin time (aPTT) ≤1.5 × the upper limit of normal (ULN).
• c. Total serum bilirubin ≤1.5 × ULN. For participants with Gilbert syndrome or indirect bilirubin elevation of extrahepatic origin, total bilirubin must be ≤3 × ULN.
• d. Aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase ≤2.5 × ULN.
• e. Pulmonary function indicating ability to tolerate surgery.
• Women who are not pregnant or women of childbearing potential must be willing to use highly effective contraception during the study and for at least 120 days after the last dose of disitamab vedotin or toripalimab, whichever occurs later, and must have a negative urine or serum pregnancy test within 7 days before enrollment. Non-sterilized male participants must be willing to use highly effective contraception during the study and for at least 120 days after the last dose of disitamab vedotin or toripalimab, whichever occurs later.