Sequential Gemcitabine Plus Docetaxel Versus Gemcitabine Plus Mitomycin C for BCG-Unresponsive Non-Muscle-Invasive Bladder Cancer

This prospective, randomized, open-label, phase II clinical trial compares two sequential intravesical chemotherapy regimens in patients with bacillus Calmette-Guérin (BCG)-unresponsive high-grade non-muscle-invasive bladder cancer (NMIBC) following complete transurethral resection of bladder tumor (TURBT). Participants are randomized in a 1:1 ratio to receive sequential intravesical gemcitabine plus docetaxel or sequential intravesical gemcitabine plus mitomycin C. The primary objective is to compare 12-month event-free survival between treatment groups. Secondary objectives include evaluation of cystectomy-free survival, progression-free survival, treatment safety, tolerability, and patient-reported quality of life.

Inclusion Criteria: 1. Age ≥18 years. 2. Histologically confirmed BCG-unresponsive non-muscle-invasive urothelial bladder cancer (NMIBC). 3. Complete transurethral resection of bladder tumor (TURBT) before study treatment. 4. Intermediate- or high-risk NMIBC according to current clinical guidelines. 5. Candidate for intravesical chemotherapy. 6. ECOG performance status 0-2. 7. Adequate hematologic, renal, and hepatic function. 8. Written informed consent. Exclusion Criteria: 1. Muscle-invasive (≥T2), locally advanced, or metastatic urothelial carcinoma. 2. Upper urinary tract urothelial carcinoma requiring treatment. 3. Previous hypersensitivity to gemcitabine, docetaxel, mitomycin C, or formulation components. 4. Active uncontrolled urinary tract infection. 5. Pregnancy or breastfeeding. 6. Concurrent participation in another interventional clinical trial. 7. Any serious uncontrolled medical condition that, in the investigator's opinion, would interfere with study participation or interpretation of results.