Intravesical gemcitabine and docetaxel combined with intravenous tislelizumab as a durable strategy for high-risk non–muscle-invasive bladder cancer.

703 Background: For decades, intravesical Bacillus Calmette-Guérin (BCG) has been the standard treatment for high-risk non-muscle-invasive bladder cancer (HR NMIBC). However, its poor tolerability and limited availability underscore the urgent need for more effective therapies. Intravesical sequential gemcitabine and docetaxel (GemDoce) has demonstrated efficacy in HR NMIBC, and immune checkpoint inhibitors (ICIs) have shown effectiveness as second-line therapy for patients with BCG-unresponsive NMIBC. Nevertheless, the combination of immunotherapy with intravesical GemDoce has not yet been reported. Methods: We retrospectively analyzed HR NMIBC patients, who received intravesical GemDoce combined with intravenous tislelizumab at Fujian Medical University Union Hospital from February 2023 to August 2024. Induction GemDoce was administered weekly for 6 weeks, then monthly maintenance. Tislelizumab started during the second GemDoce treatment and continued every 4 weeks. Inclusion required at least 6 weekly GemDoce after complete transurethral resection of bladder tumor (TURBT). Data including patient clinicopathologic features, treatment history, adverse events (AEs), and oncologic outcomes were retrospectively reviewed and analyzed. Results: 30 patients included in study, with a median number of 16 (range:6-22) GemDoce treatments and 12 (range:2-18) tislelizumab cycles. Median age was 70 (range:49-80) years. All patients had papillary disease with or without CIS, including 11 (36.7%) with HGTa and 19 (63.3%) with HGT1. CIS with HGTa was present in 2 (6.7%) patients. 5 (16.7%) patients were BCG-naïve HR NMIBC, while 25 (83.3%) patients were recurrent HR NMIBC. Most patients were male (90%, 27/30), and 56.7% (17/30) had a smoking history. Treatment was well tolerated with no discontinuations or dose reductions. In total, 12 (40%) patients reported AEs following treatment, all of which were grade 1-2. Median follow-up of 11.5 (range:2-18) months, no patients had recurrence, underwent RC, or died. Conclusions: These results suggest that intravesical GemDoce with intravenous tislelizumab is an effective and tolerable treatment option for patients with HR NMIBC. Further prospective study is warranted.