Li, Roger

741 Background: A significant treatment gap exists for efficacious, well-tolerated bladder-sparing options for patients with HR BCG-UR NMIBC with CIS. Cretostimogene is an oncolytic immunotherapy with dual mechanisms of action. It replicates in and lyses cancer cells with Rb-E2F pathway alterations, while simultaneously amplifying an anti-tumor immune response, further mediated by the GM-CSF transgene. BOND-003 (NCT04452591) is a phase-3 study evaluating the efficacy and safety of cretostimogene in patients with HR BCG-UR NMIBC with CIS +/- HG Ta/T1 (Cohort C) and HG Ta/T1 only (Cohort P). We report data on radical cystectomy performed post-recurrence or progression on Cohort C. Methods: 112 patients were enrolled. Participants had previously received adequate BCG and were considered BCG-UR by the FDA definition. Cretostimogene treatment consisted of a 6 weekly induction course, followed by 3 weekly maintenance cycles every 3 months at year one and every 6 months during years 2-3. Repeat induction was permitted at Month 3, if persistent HG Ta or CIS. Response assessments included serial cystoscopy, urine cytology, and mandatory mapping biopsy at 12 mo, with centralized review of all pathology. The primary endpoint was Complete Response (CR) at any time. Cystectomy-Free Survival (CFS) and Progression-Free Survival (PFS) were key secondary endpoints. Results: As of the June 23, 2025 data cutoff (median follow-up of 25.8 months), the CR rate at any time is 75.5% (83/110) (95% CI 66.3-83.2%). Kaplan-Meier estimates of 12- and 24-month DoR are 64.2% (95% CI 52.5-73.8%) and 60.1% (95% CI 48.2-70.0%), respectively, with a median DoR of 27.9 months (95% CI 14.3-NE%) and ongoing. The 12- and 24- month CR rate is 46.4% (51/110) (95% CI 36.8-56.1%) and 41.8% (46/110) (95% CI 32.5-51.6%), respectively. The 12- and 24-month CFS rates are 89.2 (95% CI 81.3-93.9) and 81.3% (71.8-87.8), respectively, with median CFS not reached. Among 18 patients who underwent radical cystectomy post-disease recurrence or progression; 15 (83.3%) had NMIBC or pT0 on final pathology. At 12- and 24- months, 96.6% are free from ≥T2 progression. Cretostimogene has a well-tolerated safety profile, with no grade ≥3 treatment-related adverse events. Conclusions: Cretostimogene offers distinct advantages with its mechanism of action, efficacy, durability and safety profile for the treatment of HR BCG-UR NMIBC. Furthermore, a significant proportion of patients receiving cretostimogene remained progression-free and avoided radical cystectomy. Most patients who underwent radical cystectomy had NMIBC or pT0 on final pathology maintaining a window of opportunity. Ongoing and future investigations of cretostimogene, as monotherapy and in rational combinations, may address the considerable unmet need for patients with bladder cancer. Clinical trial information: NCT04452591 .

Objectives To compare survival and oncological outcomes of cisplatin‐ineligible patients (Cis‐I) and cisplatin‐eligible (Cis‐E) patients with muscle‐invasive bladder cancer (MIBC) undergoing immediate radical cystectomy (IRC), as IRC is currently considered the standard‐of‐care for Cis‐I patients with MIBC. Patients and Methods Data from patients with clinical (c)T2–4cN0–1M0 MIBC undergoing IRC, between 2006 and 2021, were retrospectively analysed from four tertiary care centres in the United States. Overall, recurrence‐free and event‐free survival were described using the Kaplan–Meier method and tested using the log‐rank test. For context, we compared survival outcomes against those in Cis‐E patients with MIBC undergoing IRC from the Southwest Oncology Group (SWOG)‐8710 trial. Results Overall, 379 Cis‐I and 125 Cis‐E patients with cT2–4cN0–1M0 MIBC who underwent IRC were included. Cis‐I patients included 44.8% cT3/4 vs 60% cT3/4 in the Cis‐E group. Overall, 83.3% of Cis‐I and 79.2% of Cis‐E patients died during follow‐up. The median event‐free and overall survival were 12.1 and 14.5 months for the Cis‐I group and 28.8 and 60.1 months for the Cis‐E group ( P < 0.001). [Correction added on 10 October 2025, after first online publication: The preceding sentence has been revised in this version.] Limitations include retrospective comparison of contemporary multi‐institutional data with that of a randomised control trial. Conclusions The Cis‐I patients with MIBC undergoing IRC fared poorly, with a median overall survival of 14.5 (95% confidence interval 11.1–17.9) months, mostly due to non‐cancer‐related deaths. These results provide a benchmark for clinical trials exploring novel agents or alternative chemotherapy regimens in Cis‐I patients with MIBC.

4568 Background: The 2IR immune response score was initially developed using bulk RNA sequencing of pre-treatment tissue from ImVigor 210 and CheckMate 275 trials, however these trials enrolled patients (pts) with pure urothelial carcinoma (pUC) histology. Patients with hsUC often exhibit worse response to immune checkpoint inibitors (ICI) than patients with pUC. Here, we evaluated the 2IR score as a prognostic or predictive biomarker in real-world pts with hsUC. Methods: Specimens from pts with pUC (n = 1677) and hsUC (n = 417) were profiled at Caris Life Sciences (Phoenix, AZ) using next generation sequencing (NGS) of DNA and RNA. HsUC histologies included majority ( > 50%) squamous (n = 340), sarcomatoid (n = 51), neuroendocrine (n = 20), and micropapillary (n = 6) component. 2IR was calculated by comparative RNA expression of 10 adaptive immune genes and 39 pro-tumorigenic genes. Tumors were classified as 2IR-Low (2IR ≤ -0.5), -Mid (-0.5 < 2IR < 0), and -High (2IR ≥ 0), as previously described (Wang et al., 2022). Spearman correlation analysis was utilized to compare 2IR with tumor mutation burden (TMB), interferon score (IFN) and the tumor microenvironment (TME) cell fractions estimated using quanTIseq. Clinical outcomes included real-world overall survival (rwOS) from ICI start to last contact and time on treatment (ToT) with pembrolizumab, obtained via matched insurance claims data and calculated using Kaplan-Meier methods, while Hazard ratio (HR) was calculated by Cox proportional model. Results: For patients with hsUC, distribution of 2IR score was High 5.76%, Mid 33.3%, and Low 60.9%. Median 2IR score was significantly lower in squamous (-0.60, p < 0.0001) and sarcomatoid UC (-0.82, p < 0.0001) compared to pUC (-0.41) and significantly higher in neuroendocrine UC (-0.15, p = 0.003). Among patients with hsUC, median rwOS was significantly longer for patients with high/mid 2IR score compared to low 2IR score (25.3 [10.9-39.3] months vs. 8.7 [6.2-11.3] months; HR 0.52, 95% CI 0.34 – 0.78, p = 0.0017). ToT with pembrolizumab was also significantly longer for high/mid 2IR score compared to low 2IR score (3.0 [1.4-5.5] months vs. 2.1 [1.4-3.3] months; HR 0.68, 95% CI 0.46-1.00, p = 0.0471). Similar to pUC, 2IR score in patients with squamous UC was positively associated with CD8 T cell infiltration (r = 0.39; p < 0.0001), IFN score (r = 0.41, p < 0.0001), and TMB (r = 0.20, p < 0.001) and negatively associated with M1 macrophage infiltration (r = -0.25, p < 0.0001). 2IR scores in hsUC correlated positively but not significantly with mutations in TP53 (Median: -0.59 vs -0.62, p = 0.067) and PIK3CA (Median: -0.56 vs -0.61, p = 0.172) and negatively with mutations in CDKN2A (Median: -0.67 vs -0.59, p = 0.052). Conclusions: In a real-world cohort of patients with hsUC, we show the 2IR score may be prognostic for rwOS and predictive for pembrolizumab ToT. Prospective studies are needed to further validate this biomarker for use in this population.

831 Background: Long non-coding RNA (lncRNA)-based genomic profiling has suggested utility to identify a distinct tumor subgroup corresponding to a favorable prognosis in patients with bladder cancer. Here, we further evaluate a genomic classifier in a cohort of patients undergoing radical cystectomy (RC). Methods: Transcriptome-wide expression profiling using Decipher Bladder was performed on TURBT samples from a cohort of patients with high grade, clinically organ confined (cTa-T2N0M0) UC who subsequently underwent RC without any neoadjuvant therapy (n=226). LncRNA-based luminal favorable status was determined using a previously developed genomic classifier. The primary endpoint was overall survival (OS) following surgery. Secondary endpoints included cancer-specific mortality and upstaging at RC. Results: In the study, 134 patients were clinical NMIBC (cTa/Tis/T1) and 92 patients were cT2. We identified 60 patients with luminal favorable subtype, all of which showed robust gene expression patterns associated with less aggressive bladder cancer biology. On MVA, patients with the luminal favorable subtype (vs. without) were significantly associated with lower odds of upstaging to pT3+ disease (OR [95% CI] 0.32 [0.12-0.82], p = 0.02), any upstaging (OR [95% CI] 0.41 [0.20-0.83], p = 0.01), and any upstaging and/or pN+ (OR [95% CI] 0.50 [0.25-1.00], p = 0.05). Luminal favorable bladder cancer was significantly associated with better OS (HR 0.33 [95% CI 0.15-0.74], p=0.007). Conclusions: This study validates the performance of the genomic classifier for identifying urothelial carcinomas with a luminal favorable subtype, harboring less aggressive tumor biology.

Objective To further evaluate a genomic classifier (GC) in a cohort of patients undergoing radical cystectomy (RC), as long non‐coding RNA (lncRNA)‐based genomic profiling has suggested utility in identifying a distinct tumour subgroup corresponding to a favourable prognosis in patients with bladder cancer. Patients and Methods Transcriptome‐wide expression profiling using Decipher Bladder was performed on transurethral resection of bladder tumour samples from a cohort of patients with high‐grade, clinically organ‐confined (cTa–T2N0M0) urothelial carcinoma (UC) who subsequently underwent RC without any neoadjuvant therapy ( n = 226). The lncRNA‐based luminal favourable status was determined using a previously developed GC. The primary endpoint was overall survival (OS) after RC. Secondary endpoints included cancer‐specific mortality and upstaging at RC. Results In the study, 134 patients were clinical non‐muscle‐invasive bladder cancer (cTa/Tis/T1) and 92 patients were cT2. We identified 60 patients with luminal favourable subtype, all of which showed robust gene expression patterns associated with less aggressive bladder cancer biology. On multivariate analysis, patients with the luminal favourable subtype (vs without) were significantly associated with lower odds of upstaging to pathological (p)T3+ disease (odds ratio [OR] 0.32, 95% confidence interval [CI] 0.12–0.82; P = 0.02), any upstaging (OR 0.41, 95% CI 0.20–0.83; P = 0.01), and any upstaging and/or pN+ (OR 0.50, 95% CI 0.25–1.00; P = 0.05). Luminal favourable bladder cancer was significantly associated with better OS (hazard ratio 0.33, 95% CI 0.15–0.74; P = 0.007). Conclusions This study validates the performance of the GC for identifying UCs with a luminal favourable subtype, harbouring less aggressive tumour biology.

4601 Background: Cretostimogene grenadenorepvec is a type-5 oncolytic adenovirus designed to selectively replicate in bladder cancer cells with alterations in the retinoblastoma pathway. Additionally, the virus is engineered to express the GM-CSF transgene, resulting in a potent oncolytic immunotherapy mode of action. Cretostimogene monotherapy recently received Food and Drug Administration (FDA) Fast Track and Breakthrough Therapy Designations (BTD) in the BCG-Unresponsive, High-Risk, non-Muscle Invasive Bladder Cancer with Carcinoma in Situ (BCG-UR HR NMIBC with CIS) indication with a Complete Response (CR) at any time rate of 76%. This phase-2 study assessed the potential synergy between intravesical cretostimogene and pembrolizumab in patients with BCG-UR, HR NMIBC, with CIS, with or without Ta/T1 tumors. This combination has also received BTD from the FDA. Methods: 35 pts were treated with cretostimogene (1x1012 viral particles) in combination with pembrolizumab at a dose of 400 mg IV q6 weeks. Cretostimogene induction was given as 6 weekly intravesical instillations followed by 3 weekly maintenance doses at months 3, 6, 9, 12, and 18. Pts with persistent CIS or high-grade Ta tumors at the 3mo assessment were eligible for re-induction. Pembrolizumab was administered for up to 24mo. Response assessments included cystoscopy, urine cytology, cross-sectional imaging, and mandatory bladder mapping biopsies at 12mo. The primary endpoint was CR at 12mo. Secondary endpoints included CR at any time, duration of response (DOR), CR at 24mo, cystectomy-free survival, and safety. Exploratory endpoints included analyses of baseline viral receptor expression, free E2F levels, PD-L1 status, urinary cytokine panels and measures of viral replication. Results: 30/35 pts are evaluable per protocol for the primary endpoint. Five pts discontinued prior to the 12mo time point. The CR rate in the Intention to Treat (ITT) population at 12mo and any time, was 57% (20/35) (95% CI 40-73%) and 83% (29/35) (95% CI 66-93%), respectively. Median DOR has not been reached but exceeds 21mo. The current CR rate in the ITT population at 24mo is 46% (16/35) (95% CI 29-63%). Three pts have yet to reach the 24mo time point. Cystectomy-free survival at 21mo is 80%. Complete data on the ITT and evaluable patient cohorts will be presented. Analyses of treatment-related adverse events (AE) are consistent with the individual agents and demonstrate no synergistic toxicity. Conclusions: The efficacy and safety of cretostimogene plus pembrolizumab for treatment of BCG-UR, HR NMIBC with CIS demonstrates best-in-class CR and DOR compared to current FDA-approved therapies, with an acceptable AE profile. Further investigation of this promising combination therapy is warranted and may serve to address a considerable unmet need. Clinical trial information: NCT04387461 .

Objective To investigate the optimal number of induction chemotherapy cycles needed to achieve a pathological response in patients with clinically lymph node‐positive (cN+) bladder cancer (BCa) who received three or four cycles of induction chemotherapy followed by consolidative radical cystectomy (RC) with pelvic lymph node dissection. Patients and Methods We included 388 patients who received three or four cycles of cisplatin/gemcitabine or (dose‐dense) methotrexate, vinblastine, doxorubicin, and cisplatin (MVAC), followed by consolidative RC for cTanyN1–3M0 BCa. We compared pathological complete (pCR = ypT0N0) and objective response (pOR = yp ≤T1N0) between treatment groups. Predictors of pCR and/or pOR were assessed using uni‐ and multivariable logistic regression analysis. The secondary endpoints were overall (OS) and cancer‐specific survival (CSS). We evaluated the association between the number of induction chemotherapy cycles administered and survival outcomes on multivariable Cox regression. Results Overall, 101 and 287 patients received three or four cycles of induction chemotherapy, respectively. Of these, 72 (19%) and 128 (33%) achieved pCR and pOR response, respectively. The pCR (20%, 18%) and pOR (40%, 31%) rates did not differ significantly between patients receiving three or four cycles ( P > 0.05). The number of cycles was not associated with pCR or pOR on multivariable logistic regression analyses. The 2‐year OS estimates were 63% (95% confidence interval [CI] 0.53–0.74) and 63% (95% CI 0.58–0.7) for patients receiving three or four cycles, respectively. Receiving three vs four cycles was not associated with OS and CSS on uni‐ or multivariable Cox regression analyses. Conclusion Pathological response and survival outcomes did not differ between administering three or four induction chemotherapy cycles in patients with cN+ BCa. A fewer cycles (minimum three) may be oncologically sufficient in patients with cN+ BCa, while decreasing the wait for definitive local therapy in those patients who end up without a response to chemotherapy. This warrants further validation.

Objectives To assess the safety profile of antegrade mitomycin gel instillation through a percutaneous nephrostomy tube (PCNT) for upper tract urothelial carcinoma (UTUC) with the aim of decreasing morbidity associated with therapy. Patients and Methods Patients undergoing antegrade administration of mitomycin gel via PCNT were retrospectively included for analysis from four tertiary referral centres between 2020 and 2022. The primary outcome was safety profile, as graded by Common Terminology Criteria for Adverse Events (v5.0). Post‐therapy disease burden was assessed by primary disease evaluation (PDE) via ureteroscopy. Results Thirty‐two patients received at least one dose of mitomycin gel via PCNT for UTUC, 29 of whom completed induction and underwent PDE. Thirteen patients (41%) had residual tumour present prior to induction therapy. At a median of 15.0 months following first dose of induction therapy, ureteric stenosis occurred in three patients (9%), all of whom were treated without later recurrence or chronic stenosis. Other adverse events included fatigue (27%), flank pain (19%), urinary tract infection (12%), sepsis (8%) and haematuria (8%). No patients had impaired renal function during follow‐up and there were no treatment‐related deaths. Seventeen patients (59%) had no evidence of disease at PDE and have not experienced recurrence at a median follow‐up of 13.0 months post induction. Conclusions Administration of mitomycin gel via a PCNT offers a low rate of ureteric stenosis, demonstrates a favourable safety profile, and is administered without general anaesthesia.