Efficacy and safety of tislelizumab (T) combined with gemcitabine and cisplatin (GC) for patients with localized muscle-invasive bladder cancer (MIBC) after radical transurethral resection of bladder tumor/partial cystectomy: A prospective, phase II

784 Background: Transurethral resection of bladder tumor (TURBT) combined with concurrent chemoradiotherapy is the standard treatment for bladder preservation in MIBC. TURBT alone and partial cystectomy are only suitable for selected patients with solitary tumors, T2, and tumors in the bladder diverticulum while patients could have tumor recurrence after surgery. This prospective phase II study aims to explore the efficacy and safety of T combined with GC after radical TURBT or partial cystectomy as bladder preservation therapy in patients with PD-L1 positive MIBC. Methods: Eligible patients had clinical stage T2-T3N0M0, histologically confirmed PD-L1 positive urothelial carcinoma, no prior systemic treatment, and no residual tumor after radical TURBT or partial cystectomy. Patients received T combined with GC within 8 weeks of local treatment (G 1000mg/m2, d1, d8; C 70mg/m2, d1, IV, q3w, for a total of 6 cycles. T 200mg, d8, IV, q3w, for a total of 8 cycles). The primary endpoint was 1-year bladder intact disease-free survival rate. Secondary endpoints included 2-year bladder intact disease-free survival rate, metastasis-free survival, time to salvage cystectomy, overall survival, and safety. Results: From August 2022 to October 2024, a total of 13 patients were enrolled in the study. Median age was 70 years (65-75). Twelve patients were staged as pT2 and 1 patient had pT3. Twelve patients were evaluable for efficacy and 1 patient withdrew the consent. Seven patients underwent TURBT and 5 patients underwent partial cystectomy. Median follow-up time was 8.0 months. One patient had non-muscle-invasive bladder cancer recurrence and receive intravesical BCG instillation while the remains had no recurrence of disease. 1-year bladder-intact disease-free survival rate was 100%. Grade 3 or higher adverse events occurred in 33.3% of patients. No new safety signals were observed. Conclusions: The study demonstrated that combination of T and GC after complete resection of tumor seemed promising as bladder preservation strategy in selected patients. Further recruitment is ongoing. Clinical trial information: NCT05401279 .