Real-world outcomes of nadofaragene firadenovec in BCG-unresponsive non-muscle invasive bladder cancer.

716 Background: Nadofaragene firadenovec is an FDA-approved gene therapy for Bacillus Calmette-Guérin (BCG) unresponsive non-muscle invasive bladder cancer (NMIBC) with promising clinical trial results. However, real-world post-marketing efficacy or safety data remain lacking. We evaluated complete response rates and safety in a multisite experience. Methods: Per IRB protocol, we analyzed patients treated with nadofaragene firadenovec for BCG-unresponsive NMIBC across three Mayo Clinic sites. Outcomes included complete response (CR), high-grade recurrence-free survival (HGRFS), cystectomy-free survival (CFS), overall survival (OS), and adverse events (AEs). CR and HGRFS were reported for patients with carcinoma in situ (CIS) and patients with Ta/T1 without CIS respectively. Failure to retain was defined as any medication loss, including leakage around the catheter or early voiding. Results: Between November 2023 and October 2024, 45 patients were treated with nadofaragene firadenovec for BCG-unresponsive NMIBC. Fifteen patients with follow-up less than 6 months and one patient with extensive metastatic disease identified one week after first instillation were excluded from efficacy analysis. Our efficacy-evaluable population of 29 patients with median follow-up of 8.2 months is summarized in the Table. CR/HGRFS at 3 and 6 months was 72% and 62% respectively. CFS was 94% and OS was 100% at 6 months. Three patients experienced disease progression during follow-up: one to T1, another to T2, and a third with metastases to the abdomen and lungs. A separate patient developed a metachronous upper tract urothelial carcinoma (pT2) without bladder recurrence. Bladder spasms (62%) and failure to retain (31%) were the most common AEs. Most AEs were low-grade, although four (9%) patients had grade 3 events (fatigue, fever, and dizziness). No grade 4-5 AEs were reported. Conclusions: Early real-world data demonstrates encouraging clinical complete response rates in patients with BCG-unresponsive NMIBC and a favorable safety profile. Further investigation with larger cohorts and longer follow-up is warranted. Evaluable patients (N=29) CIS cohort (N=15) Ta/T1 only cohort (N=14) Prior pembrolizumab (N=9) Prior intravesical chemotherapy (N=16) Age, years 72 (67-77) 74 (69-77) 71 (67-77) 69 (67-78) 73 (67-81) Elixhauser Index 5 (4-6) 5 (4-7) 5 (4-6) 5 (3-5) 5 (3-6) Prior BCG instillations 12 (10-14) 12 (12-15) 11 (8-13) 12 (12-12) 12 (11-13) Prior intravesical chemotherapy among recipients 6 (6-11) 6 (6-10) 6 (6-11) 10 (7-12) 6 (6-11) Prior pembrolizumab doses among recipients 7 (4-8) 8 (7-8) 4 (4-4) 7 (4-8) 8 (5-8) Follow-up, months 8.2 (6.9-9.5) 7.6 (6.9-9.5) 8.5 (6.9-9.4) 9.1 (8.0-10.1) 8.6 (6.7-9.9) 3-month CR/HGRFS 72% [53-87] 73% [45-92] 71% [42-92] 67% [30-93] 56% [30-80] 6-month CR/HGRFS 62% [42-79] 67% [38-88] 57% [29-82] 44% [14-79] 44% [20-70] Data are median (IQR) or % [95% CI].