Response to primary chemoablation with UGN-102 in different EOTRC risk groups.

733 Background: The ENVISION phase 3 study (NCT05243550) treated patients with recurrent low-grade intermediate-risk non-muscle-invasive bladder cancer (LG-IR-NMIBC) with UGN-102, a reverse thermal hydrogel administered intravesically containing 75 mg mitomycin. Complete response (CR) rate at 3 months was 79.6% (95% confidence interval CI: 73.9, 84.5) with a 72.2% (95% CI: 64.1, 78.8) 1 probability of remaining in response (DoR) 24 months later. The European Organization for Research and Treatment of Cancer (EORTC) recurrence score tables provide estimates of recurrence based on baseline prognostic factors. We conducted a post-hoc analysis of CR and DoR by EORTC recurrence score subgroup. Methods: 240 patients with recurrent LG-IR-NMIBC received ≥1 dose of UGN-102. CR was assessed at 3 months using cystoscopy, urine cytology testing, and for-cause biopsy. Patients achieving CR entered the follow-up period and are being assessed for recurrence or progression for up to 5 years. CR at 3 months and probability of maintaining CR at 24 months (DoR) in patients with EORTC recurrence scores of 1-4, 5-9 and 10-17 were calculated. DoR was calculated using the Kaplan–Meier (KM) estimation method. Results: The median (range) EORTC recurrence score was 7 (2-13). CR rate at 3 months was 83.9%, 81.2% and 60% for patients with recurrence scores of 1-4 (n=31), 5-9 (n=191) and 10-17 (n=15), respectively. Of the patients with CR at 3 months, 26.9%, 23.9% and 33.3% (for recurrence scores of 1-4, 5-9 and 10-17) experienced recurrence of LG disease, progression (either in stage or grade), or death by 24 months. The KM estimate of median DoR was not estimable for any group due to the low event rates. Conclusions: UGN-102 demonstrated robust complete response rates across all EORTC recurrence score subgroups, including patients with higher baseline recurrence risk. The majority of patients remained recurrence-free at 24 months. Despite the post-hoc design and small subgroup sizes, these findings suggest UGN-102 provides durable and clinically meaningful disease control in recurrent LG-IR-NMIBC. Clinical trial information: NCT05243550 . EORTC recurrence score group 1-4 N=31 5-9 N=191 10-17 (N=15) CR at 3 months, n (%) 26/31 (83.9) 155/191 (81.2) 9/15 (60) CRR (95% CI) 83.9 (66.3-94.5) 81.2 (74.9-86.4) 60.0 (32.3, 83.7) Recurrence 24 months*, n (%)Recurrence of LG diseaseProgressionDeath 7/26 (26.9) 5/26 (19.2) 0 2/26 (7.7) 37/155 (23.9) 27/155 (17.4) 7/155 (4.5) 3/155 (1.9) 3/9 (33.3) 3/9 (33.3) 0 0 Probability of remaining in response at 24 months, %, 95% CI** 67.4 (43.2-83.1) 73.7 (64.6-80.8) 66.7 (28.2-87.8) Median duration of follow up, months, 95% CI*** 23.29 (23.03-23.92) 23.72 (23.66-23.92) 23.90 (23.72-NE) *24 months after 3-month CR. **Calculated using the KM method, with Brookmeyer–Crowley CIs. *** Estimated using reverse KM method. CI, confidence interval; CRR, complete response rate. 1. Prasad SM, et al. J Urol. 2025;213:205–16.