Intravesical gemcitabine and docetaxel in the treatment of BCG-naïve non–muscle invasive urothelial carcinoma of the bladder: Updates from a phase 2 trial

507 Background: Combination intravesical Gemcitabine and Docetaxel (GEMDOCE) has demonstrated benefit for bacillus Calmette-Guérin (BCG) unresponsive non-muscle invasive bladder cancer (NMIBC) in retrospective series and is now being widely utilized as salvage therapy. BCG therapy is fraught with frequent drug shortages and some patients are unable to tolerate BCG due to side effects. Given ongoing BCG shortages as well as the promising efficacy and tolerability of GEMDOCE as a salvage therapy, our objective was to investigate the safety and efficacy of intravesical GEMDOCE for high-risk (HR) BCG-naïve NMIBC in a prospective manner. Methods: This study is an IRB-approved prospective single-arm open-label phase II trial for patients with BCG-naïve HR NMIBC. Intravesical gemcitabine (1,000 mg)/docetaxel (40 mg) in 100mL normal saline is given weekly for 6 weeks as induction followed by monthly maintenance therapy for 2 years among responders. The primary endpoint was 3-month complete response (CR), defined as a negative bladder biopsy 6 weeks after induction treatment. Secondary endpoints included adverse events (AE) and 12-month CR. Results: To date, the study has fully accrued with 25 patients enrolled from July 2020-August 2022. The pre-trial pathologic stages in our cohort were as follows: HGT1 with CIS (n = 7), HGT1 without CIS (n = 6), HGTa (n = 9), and CIS alone (n = 3) (Table). All 25 patients who completed induction therapy demonstrated CR at 3 months. Eight out of 9 (89%) patients with at least 12 months of follow-up demonstrated continued CR. One patient with HGT1 + CIS on enrollment developed a recurrence at 9 months with HGTa. No enrolled patients have undergone radical cystectomy. Grade 1 AEs were common (19/25 patients, 76%) including hematuria, urinary frequency, urgency, and fatigue. Two patients (8%) experienced a Grade 3 AE including urinary retention and UTI requiring hospitalization and intravenous antibiotics. Conclusions: In this ongoing single-arm phase II trial, GEMDOCE appears to be well-tolerated with promising short-term efficacy for patients with BCG-naïve HR NMIBC. [Table: see text]