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Although predominantly urothelial, some bladder cancer and upper tract urothelial cancer (BC/UTUC) harbor histologic variants. Small cell BC (SCBC) variants comprised ˜5% of The Cancer Genome Atlas BC cohort, with a poor prognosis. We describe genomic profiles of BC/UTUC with small cell/neuroendocrine features identified in the Foundation Medicine database from June 2012 to September 2018. Of 3368 BC/UTUC samples, 3.92% (132) harbored small cell/neuroendocrine features by immunohistochemistry. Mutations were noted in: TP53 (92%), RB1 (75%), combined TP53/RB1 (72%), and TERT promoter (68%). Of the samples, 6.5% had TMB ≥ 10 mutations/Mb. RNA expression profiling of 24 pure SCBC and 51 urothelial BC (UBC) muscle-invasive samples evaluated from a separate cohort revealed a large number of differentially expressed genes with suppression of several inflammatory pathways in SCBC compared with UBC. This largest reported SCBC dataset to date confirms enrichment of signatures in SCBC similar to small cell lung cancer and describes unique gene expression compared with UBC. These findings may explain aggressive SCBC phenotype. Patient summary Small cell bladder cancer (SCBC) is an aggressive subtype that microscopically resembles aggressive small cell lung cancer (SCLC). This study confirms that SCBC shares DNA changes similar to SCLC and that SCBC expresses many genes that urothelial bladder cancer does not, possibly explaining aggressive SCBC activity.

Despite considerable advances in the management of urothelial carcinoma (UC), better risk stratification and enhanced detection of minimal residual disease are still urgent priorities to prolong survival while avoiding the morbidity of overtreatment. Circulating tumor cells and DNA (CTCs, ctDNA) are two biologically distinct "liquid biopsies" that may potentially address this need, although they have been understudied in UC to date and their relative utility is unknown. To this end, matched CTC and ctDNA samples were collected for a head-to-head comparison in a pilot study of 16 patients with metastatic UC. CTCs were defined as cytokeratin- and/or EpCAM-positive using the RareCyte direct imaging platform. ctDNA was assayed using the PlasmaSelect64 probe-capture assay. 75% of patients had detectable CTCs, and 73% had detectable somatic mutations, with no correlation between CTC count and ctDNA. 91% of patients had tissue confirmation of at least one plasma mutation and, importantly, several clinically actionable mutations were detected in plasma that were not found in the matching tumor. A ctDNA fraction of >2% was significantly associated with worse overall survival (p=0.039) whereas CTC detection was not (p=0.46). Notably, using a predefined gene panel for ctDNA detection had a high but not complete detection rate in metastatic UC, similar to what has been described for a custom tissue-personalized assay approach. In sum, both liquid biopsies show promise in UC and deserve further investigation. PATIENT SUMMARY: New "liquid biopsy" blood tests are emerging for urothelial cancer aimed at early detection and avoiding overtreatment. Our results suggest that two such tests provide complementary information: circulating tumor cells may be best for studying the biological features of a person's cancer, whereas circulating tumor DNA may be better for early detection.

Background: Standard of care for patients with muscle-invasive bladder cancer (MIBC) includes neoadjuvant cisplatin-based chemotherapy (NAC) followed by consolidative therapy with either chemoradiation or radical cystectomy (RC). Some patients experience robust pathologic responses to NAC, and these have been reported to associate with somatic mutations in specific gene pathways including DNA damage response genes. Objective: To evaluate the ability of post-NAC clinical restaging, with or without tumor sequencing, to predict final RC pathologic staging. Design, setting, and participants: We reviewed our institutional review board–approved institutional database to identify patients with MIBC who underwent NAC followed by RC from 2003 to 2016. Following NAC prior to RC, cystoscopy was performed routinely, with resection of residual visible tumor and/or tumor base (transurethral resection [TUR]). For patients with pre-NAC tumor tissue available, tumor sequencing was performed. Outcome measurements and statistical analysis: Clinical restaging and tumor sequencing were evaluated for their ability to predict the final pathologic stage accurately at RC using chi-square or Fisher’s exact test. Results and limitations: A total of 114 patients underwent restaging TUR following NAC and prior to RC. The diagnostic accuracy of post-NAC clinical restaging including TUR was poor, with 32% of patients being downstaged falsely when compared with their final RC pathology. Forty-nine patients had sequencing of pre-NAC tumor tissue, of whom 32 showed at least one mutation of interest. However, NAC responses and rates of false downstaging did not differ significantly according to tumor mutation status. Conclusions: This study highlights the inaccuracy of post-NAC clinical restaging TUR with or without adjunctive tumor mutation analysis, to assess pathologic residual disease accurately. Caution must be taken when performing post-NAC restaging, especially when considering conservative management strategies such as active surveillance on this basis. Patient summary: Several groups are evaluating whether certain patients, whose bladder cancer responds well to upfront chemotherapy, may be able to forego cystectomy safely. We demonstrate that currently available staging tools and tumor DNA sequencing cannot identify such patients reliably and accurately.

Introduction: Developing optimized bladder cancer mouse models that can be used in the evaluation of immune based therapeutics remains a high priority in ongoing research.Experimental Procedures: In previous work by our collaborators, murine cell lines were generated that recapitulate the basal (BBN964, BBN966, and BBN975) molecular subtype of human bladder cancer (Saito et al. Cancer Res. 2018;78(14):3954-3968). Here we compared their tumorigenicity and growth rates in immunocompetent C57BL/6 mice and in immunodeficient Rag1-KO mice lacking B and T cells. Changes in the tumor and stromal compartments were correlated with the differences in growth rates observed. Observations and New Data: Tumors derived from all three BBN basal cell lines grew robustly in Rag1-KO mice (10/10 BBN964 tumors, 19/19 BBN966 tumors and 19/19 BBN975 tumors >100 mm3 by 10 weeks post-injection). Conversely, very few tumors grew in immunocompetent (C57BL/6, e.g. B6) mice (0/9 BBN964 at 8 weeks, 0/17 BBN966 at 16 weeks, 4/15 BBN975 at 9 weeks). BBN966 tumors conditioned to grow in Rag1-KO mice were also highly tumorigenic when they were subsequently transferred into immunocompetent mice (Rag1-KO ◊ B6, 16/20 mice with tumors >100 mm3 at 4 weeks), and they displayed increased tumorigenicity when they were reintroduced into immunodeficient mice (Rag1-KO ◊ Rag1-KO, 20/20 mice with tumors >100 mm3 at 3 weeks). BBN966 tumors harvested from B6 mice and passaged in vitro for 5 weeks maintained tumorigenicity when reimplanted into immunocompetent mice, and BBN966 tumors grown in female B6 mice grew robustly when transferred into male B6 mice. Bulk RNA sequencing of tumors comparing the BBN966 Rag1-KO (1st passage) to BBN966 Rag1-KO (2nd passage) demonstrated decreased expression of genes associated with tumor infiltrating macrophages in the 2nd passage tumors. Conclusions: Our results demonstrate that basal BBN syngeneic bladder tumors display markedly different growth rates in wild-type and T- and B-cell-deficient mice. The results suggest that adaptive immunity controls basal bladder cancer tumorigenicity, which is consistent with the immune infiltrated landscape observed in basal human bladder cancers. Further results described in this poster will include deeper molecular characterizations of the immune microenvironments of these tumors. Citation Format: Burles Avner Johnson, Mingxiao Feng, Woonyoung Choi, Gabriela Colocho, Alyssa Arbuiso, Samuel Jin, Adam K. Aragaki, Charles Ruland, Stanley Rapiey, Noah M. Hahn, David J. McConkey. Control of the Basal Molecular Subtype of Murine Bladder Cancer by Adaptive Immunity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 612.

Objectives: To compare clinical outcomes between patients with locally advanced (unresectable) or metastatic urothelial carcinoma (aUC) in the upper and lower urinary tract receiving immune checkpoint inhibitors (ICIs). Patients and methods: We performed a retrospective cohort study collecting clinicopathological, treatment, and outcome data for patients with aUC receiving ICIs from 2013 to 2020 across 24 institutions. We compared the objective response rate (ORR), overall survival (OS), and progression-free survival (PFS) between patients with upper and lower tract UC (UTUC, LTUC). Uni- and multivariable logistic and Cox regression were used to assess the effect of UTUC on ORR, OS, and PFS. Subgroup analyses were performed stratified based on histology (pure, mixed) and line of treatment (first line, subsequent line). Results: Out of a total of 746 eligible patients, 707, 717, and 738 were included in the ORR, OS, and PFS analyses, respectively. Our results did not contradict the hypothesis that patients with UTUC and LTUC had similar ORRs (24% vs 28% ; adjusted odds ratio [aOR] 0.73, 95% confidence interval [CI] 0.43-1.24), OS (median 9.8 vs 9.6 months ; adjusted hazard ratio [aHR] 0.93, 95% CI 0.73- 1.19), and PFS (median 4.3 vs 4.1 months ; aHR 1.01, 95% CI 0.81-1.27). Patients with mixed- histology UTUC had a significantly lower ORR and shorter PFS vs mixed-histology LTUC (aOR 0.20, 95% CI 0.05-0.91 and aHR 1.66, 95% CI 1.06-2.59), respectively). Conclusion: Overall, patients with UTUC and LTUC receiving ICIs have comparable treatment response and outcomes. Subgroup analyses based on histology showed that those with mixed- histology UTUC had a lower ORR and shorter PFS compared to mixed-histology LTUC. Further studies and evaluation of molecular biomarkers can help refine patient selection for immunotherapy.

PURPOSE: Current first-line treatment options in patients with metastatic urothelial carcinoma (mUC) unfit to receive cisplatin-containing chemotherapy include PD-1/L1 inhibitors and carboplatin-containing chemotherapy. However, the optimal sequencing of these therapies remains unclear. MATERIAL AND METHODS: We conducted a multicenter retrospective analysis. Consecutive cisplatin-ineligible patients with mUC treated with first-line carboplatin-containing chemotherapy followed sequentially by second-line PD-1/L1 inhibitor, or the reverse order, were included. Patient demographics, objective response, time to treatment failure for first-line (TTF1) and second-line (TTF2) therapy, interval between end of first-line and initiation of second-line treatment (Interval(1L-2L)), and overall survival (OS) were collected. Multivariate analysis was conducted to examine the association of sequencing on OS. RESULTS: In this multicenter retrospective study, we identified 146 cisplatin-ineligible patients with mUC treated with first-line (1L) PD-1/L1 inhibitor therapy followed by second-line (2L) carboplatin-containing chemotherapy (Group 1, n=43) or the reverse sequence (Group 2, n=103). In the overall cohort, median age was 72, 76% were men, and 18% had liver metastasis. In both groups, objective response rates were higher with carboplatin-containing chemotherapy (45.6% 1L, 44.2% 2L) compared to PD-1/L1 inhibitors (9.3% 1L, 21.3% 2L). On multivariate analysis, treatment sequence was not associated with overall survival (HR 1.05, p=0.85). Site of metastasis was the only factor significantly associated with overall survival (p=0.002). CONCLUSIONS: In this biomarker-unselected cohort of cisplatin-ineligible patients with mUC, PD-1/L1 inhibitor followed by carboplatin-containing chemotherapy and the reverse sequence had comparable OS.

Immunohistochemical stains have been suggested to aid in diagnostically challenging cases of urothelial carcinoma in-situ (CIS). Although full thickness immunostaining for CK20 is supportive of CIS, a subset of CIS cases is CK20(-), the clinical significance of which was unknown. This study included 43 patients with primary diagnosis of bladder CIS including 32 with only CIS, 5 with CIS and separate noninvasive high-grade papillary urothelial carcinoma, and 6 with CIS and separate high-grade urothelial carcinoma with lamina propria invasion. Digital morphometric image analysis showed that the average nuclear areas of enlarged nuclei were similar in CK20(+) and CK20(-) CIS (26.9 vs. 24.5 µM2; P=0.31). Average Ki67 index for CK20(+) CIS was higher than CK20(-) CIS (31.1% vs. 18.3%; P=0.03). Patients with CK20(+) CIS [28 (65%)] and patients with CK20(-) CIS [15 (35%)] had the same rates of Bacillus Calmete-Guerin (BCG) failure but patients with CK20(-) CIS had higher stage progression [3 CK20(+) (11%) vs. 6 CK20(-) (40%); P=0.02]. Given recent approval of immune checkpoint inhibitors in patients with CIS refractory to BCG, programmed death ligand-1 expression and colocalization with CD8(+) lymphocytes was investigated as signature of adaptive immune response and was seen in 8 patients regardless of CK20 status and exclusively among patients who failed BCG. Our results confirm that negative CK20 IHC does not exclude CIS and that those patients have similar clinical outcomes as patients with CK20(+) CIS. Programmed death ligand-1 and CD8 colocalization seen among patients who failed BCG therapy is an easy assay to perform to identify patients who could potentially benefit from combined BCG therapy and immune checkpoint inhibition.

PURPOSE The phase II single-arm KEYNOTE-052 study evaluated the efficacy and safety of first-line pembrolizumab for patients with locally advanced or metastatic cisplatin-ineligible urothelial carcinoma (UC). PATIENTS AND METHODS Three hundred seventy patients received pembrolizumab 200 mg intravenously every 3 weeks for up to 24 months. Positive tumor programmed death ligand 1 (PD-L1) expression was defined as combined positive score (CPS) ≥ 10. Response was assessed by independent central review every 9 weeks per RECIST v1.1. The primary end point was objective response rate (ORR). RESULTS At data cutoff (September 26, 2018), the minimum follow-up was 2 years since the last patient enrolled. ORR was 28.6% (95% CI, 24.1% to 33.5%); 33 patients (8.9%) and 73 patients (19.7%) achieved complete and partial response, respectively. The median duration of response was 30.1 months (95% CI, 18.1 months to not reached [NR]); responses lasted ≥ 12 and ≥ 24 months in 67% and 52% of patients, respectively. Forty patients with complete or partial response completed 2 years of study treatment, and 32 had ongoing response at completion. Median overall survival (OS) was 11.3 months (95% CI, 9.7 to 13.1 months), and 12- and 24-month OS rates were 46.9% and 31.2%, respectively. In patients with CPS ≥ 10, ORR was 47.3% (95% CI, 37.7% to 57.0%) and median OS was 18.5 months (95% CI, 12.2 to 28.5 months). In patients with lymph node–only disease, ORR was 49.0% (95% CI, 34.8% to 63.4%), and median OS was 27.0 months (12.4 months to NR). There were no new safety signals. CONCLUSION First-line pembrolizumab confers meaningful and durable clinical response in cisplatin-ineligible patients with advanced UC and is associated with prolonged OS, particularly with PD-L1 CPS ≥ 10 and lymph node–only disease.

Urinary tract cancer can be pure urothelial carcinoma, pure nonurothelial carcinoma or variant urothelial carcinoma (defined here as mixed urothelial carcinoma). Little is known regarding outcomes for patients with variant urothelial carcinoma receiving immune checkpoint inhibitors. We hypothesized that variant urothelial carcinoma does not compromise immune checkpoint inhibitor efficacy in patients with advanced urothelial carcinoma.We performed a retrospective cohort study across 18 institutions. Demographic, clinicopathological, treatment and outcomes data were collected for patients with advanced urothelial carcinoma who received immune checkpoint inhibitors. Patients were divided into pure vs variant urothelial carcinoma subgroups, with variant urothelial carcinoma further divided by type of variant (ie squamous, neuroendocrine etc). We compared overall response rate using univariate and multivariate logistic regression and progression-free survival and overall survival using Kaplan-Meier and univariate and multivariate Cox proportional hazards.Overall 519 patients were identified, with 395, 406 and 403 included in overall response rate, overall survival and progression-free survival analyses, respectively. Overall response rate to immune checkpoint inhibitors between patients with pure vs variant urothelial carcinoma was comparable (28% vs 29%, p=0.90) without significant differences for individual subtypes vs pure urothelial carcinoma. Median overall survival for patients with pure urothelial carcinoma was 11.0 months vs 10.1 months for variant urothelial carcinoma (p=0.60), but only 4.6 months for patients with neuroendocrine features (9 patients, HR 2.75, 95% CI 1.40-5.40 vs pure urothelial carcinoma, p=0.003). Median progression-free survival was 4.1 months for pure vs 5.2 months for variant urothelial carcinoma (p=0.43) and 3.7 months for neuroendocrine features (HR 1.87, 95% CI 0.92-3.79 vs pure urothelial carcinoma, p=0.09).Overall response rate to immune checkpoint inhibitors was comparable across histological types. However, overall survival was worse for patients with tumors containing neuroendocrine features. Variant urothelial carcinoma should not exclude patients from receiving immune checkpoint inhibitors.

PURPOSE Platinum-based chemotherapy for first-line treatment of metastatic urothelial cancer is typically administered for a fixed duration followed by observation until progression. “Switch maintenance” therapy with PD-1 blockade at the time of chemotherapy cessation may be attractive for mechanistic and pragmatic reasons. PATIENTS AND METHODS Patients with metastatic urothelial cancer achieving at least stable disease on first-line platinum-based chemotherapy were enrolled. Patients were randomly assigned double-blind 1:1 to switch maintenance pembrolizumab 200 mg intravenously once every 3 weeks versus placebo for up to 24 months. Patients with disease progression on placebo could cross over to pembrolizumab. The primary objective was to determine the progression-free survival. Secondary objectives included determining overall survival as well as treatment outcomes according to PD-L1 combined positive score (CPS). RESULTS Between December 2015 and November 2018, 108 patients were randomly assigned to pembrolizumab (n = 55) or placebo (n = 53). The objective response rate was 23% with pembrolizumab and 10% with placebo. Treatment-emergent grade 3-4 adverse events occurred in 59% receiving pembrolizumab and 38% of patients receiving placebo. Progression-free survival was significantly longer with maintenance pembrolizumab versus placebo (5.4 months [95% CI, 3.1 to 7.3 months] v 3.0 months [95% CI; 2.7 to 5.5 months]; hazard ratio, 0.65; log-rank P = .04; maximum efficiency robust test P = .039). Median overall survival was 22 months (95% CI, 12.9 months to not reached) with pembrolizumab and 18.7 months (95% CI, 11.4 months to not reached) with placebo. There was no significant interaction between PD-L1 CPS ≥ 10 and treatment arm for progression-free survival or overall survival. CONCLUSION Switch maintenance pembrolizumab leads to additional objective responses in patients achieving at least stable disease with first-line platinum-based chemotherapy and prolongs progression-free survival in patients with metastatic urothelial cancer.

Background: Nonmuscle-invasive bladder cancer (NMIBC) is the most common form of bladder cancer, with high rates of disease recurrence and progression. Current treatment for high-risk NMIBC involves Bacillus Calmette-Guérin (BCG) therapy, but treatment options are limited for patients with recurrent or BCG-unresponsive disease. Aberrant programmed death 1 signaling has been implicated in BCG resistance and bladder cancer recurrence and progression, and pembrolizumab has shown efficacy in patients with BCG-unresponsive high-risk NMIBC. Aim: To describe the rationale and design for the randomized, comparator-controlled Phase III KEYNOTE-676 study, which will evaluate the efficacy and safety of pembrolizumab in combination with BCG in patients with persistent/recurrent high-risk NMIBC after BCG induction therapy. Trial registration number: NCT03711032

Background: Patients with treatment-naive advanced urothelial cancer (UC) Ineligible for cisplatin-based chemotherapy are typically older and have comorbidities, representing a difficult-to-treat population. Objective: To evaluate the safety and antitumor activity of first-line pembrolizumab in subgroups of cisplatin-ineligible older patients (aged ≥65 and ≥75 yr) with advanced UC in KEYNOTE-052 (NCT02335424), including those with poor performance status (Eastern Cooperative Oncology Group performance status score 2 [ECOG PS2]). Design, setting, and participants: Patients were cisplatin ineligible, had treatment-naive, histologically/cytologically confirmed, locally advanced/metastatic UC with measurable disease (Response Evaluation Criteria in Solid Tumors version 1.1 [RECIST v1.1]), and had ECOG PS0–2. Patient subgroups analyzed were aged ≥65 yr (n = 302), ≥75 yr (n = 179), ≥65 yr with ECOG PS2 (≥65 yr + ECOG PS2; n = 119), and ≥75 yr + ECOG PS2 (n = 78). Intervention: All patients received pembrolizumab 200 mg intravenously every 3 wk until confirmed progression, intolerable toxicity, patient withdrawal, or 24 mo of therapy. Outcome measurements and statistical analysis: The primary endpoint was objective response rate (ORR) as per RECIST v1.1. The key secondary endpoints were overall survival (OS), duration of response (DOR), and safety. Results and limitations: ORRs for the ≥65 yr, ≥75 yr, ≥65 yr + ECOG PS2, and ≥75 yr + ECOG PS2 subgroups were 29%, 27%, 29%, and 31%, respectively; rates of complete and partial responses were similar across subgroups (9%, 5%, 6%, and 6%, and 20%, 22%, 23%, and 24%, respectively). Median DOR and OS were also consistent across the ≥65 yr and ≥65 yr + ECOG PS2 subgroups and the ≥75 yr and ≥75 yr + ECOG PS2 subgroups. Study limitations included open-label design, lack of a comparator group, and nature of post hoc exploratory analysis. Conclusions: The clinical benefit of pembrolizumab in advanced UC appeared to be consistent regardless of age and/or poor performance status., Patient summary: This study looked at whether older age and poorer performance status affect how well patients with previously untreated advanced urothelial cancer ineligible for standard-of-care treatment respond to pembrolizumab. Outcomes with pembrolizumab were not affected by older age or poorer performance status, making it an effective option.

523 Background: In the TROPHY study, 8.8% of the 113 patients (pts) were enrolled post EV treatment, with ORR to SG of 30% in that small subset. Response to SG post EV in real world populations has not been previously reported. SG has accelerated FDA approval for treatment refractory UC, with ORR of 27% in the TROPHY-U-01 trial. SG was developed contemporaneously to EV, which like SG, is also an antibody-drug conjugate (ADC), composed of an alternate antibody linker and chemotherapy payload. The EV ORR is 40-52% in single agent studies, and outcomes following SG to EV have not been reported. Optimal therapy sequence for advanced UC, concerns for cross resistance between ADCs and other targeted therapies, and biomarker selection for agents is underexplored. We describe clinical outcomes in pts with advanced UC treated with SG following EV. Methods: In this retrospective study of pts with UC treated with SG after progression on EV at the Johns Hopkins Greenberg Bladder Cancer Institute between November 2020 and October 2022, 17 pts were identified. Fourteen received SG in the next line following EV, 3 had other interval therapies between EV and SG. Response was determined by physician assessed RECIST criteria. All pts were response evaluable for prior EV. Three pts died shortly after C1 SG without imaging and were not response evaluable. Results: In our cohort 8 (47%) pts were female, 3 (17.6%) were African-American and 14 (82.4%) were Caucasian. Mean age was 68.3 years. Primary location was bladder for 9 (52.9%) pts and UTUC for 7 (41.2%). One (5.9%) patient had disease in both primary sites. Two (11.8%) pts had lymph node only disease, 8 (47.1%) had metastatic disease in the lungs, 6 (35.3%) in the liver and 1(5.9%) in bone. Mean number of EV cycles was 5.9 (1-12) and PFS was 5.9 months. Best EV response was CR in 1 (5.9%), PR in 10 (58.8%), SD in 2 (11.8%) and PD in 4 (23.5%) pts. SG was dose reduced in C1 with prophylactic growth factor support in 13/17 pts in this heavily pretreated population. Mean number of SG cycles was 3.8 (1.5-6). Best SG response for the 14 response evaluable pts was PR for 3 (21.4%) pts and SD for 3 (21.4%), for a clinical benefit (CR+PR+SD) rate of 42.8%. Eight pts had best response of PD (57.1%). SG discontinuation was for PD in 8 pts (57.1%) and 4 (28.6%) due to functional decline or toxicity. One patient had PD to SG in C2 but received 3 additional cycles due to therapeutic benefit. Three (21.4%) pts continue SG, after 6 cycles with PR and after 5 and 4 cycles with SD. For 14 response evaluable pts, the PFS on SG was 2.4 months. Conclusions: In this retrospective analysis, pts with advanced UC and PD following EV had meaningful clinical benefit rate to SG of 42.8% despite dose reduction in this small late line cohort. Defining optimal sequence of ADCs and other therapies in UC remains an unmet need. Updated data will be presented.

536 Background: Cisplatin-based chemotherapy has been associated with functional cures (i.e., DDFTFS) in a small subset of patients with mUC. However, the mechanistic basis for this phenomenon has remained elusive. Immune checkpoint blockade may enhance the ability of cisplatin-based chemotherapy to cure mUC, particularly if the latter is achieved by promoting antitumor immunity. From a phase II trial evaluating a phased schedule of gemcitabine and cisplatin (GC) followed by GC plus Ipilimumab (Ipi) for mUC, 4/36 patients were treatment-free disease-free >7 years after initiation of treatment. We sought to identify the immunological mechanisms associated with functional cure of such patients. Methods: Whole exome sequencing was performed on pre-treatment archival tumor tissue. Neoantigen binding affinity was predicted using NetMHCcons. Neoantigen-specific T cell response was assessed via IFNγ ELISpot assays after co-culture of patient-derived peripheral blood CD4+ and CD8+ T cells with autologous neoantigen-pulsed antigen presenting B cells. Serum protein soluble analytes were measured using the Olink Target 96 Immuno-Oncology Panel at the pre-treatment, post-GC, and post-GC+Ipi timepoints. Results: CD4+ and CD8+ neoantigen-specific T cell reactivity was measured at serial timepoints in 2 patients achieving DDFTFS and 5 patients not achieving DDFTFS. Strikingly, peripheral blood CD4+ and CD8+ T cell reactivity to a predicted neoantigen emerged on cycle 6 day 1 (after 2 cycles of GC followed by 4 cycles of GC + Ipi) in 2/2 patients achieving DDFTFS (variant in TP53 or DHX9) but in 0/5 patients not achieving DDFTFS. Peripheral serum proteomic analysis at serial timepoints (n = 35 patients) revealed that pre-treatment, patients achieving DDFTFS demonstrated an immune activated phenotype with elevations in cytotoxic adaptive immunity markers and immune checkpoints (Table). After the addition of Ipi, patients achieving DDFTFS demonstrated decreased markers of tumor-promoting inflammation but increased markers of adaptive immunity, co-stimulation, and cytotoxicity. Conclusions: Anti-tumor immunity may underlie functional cures achieved in patients with mUC treated with cisplatin-based chemotherapy +/- immune checkpoint blockade. Probing the mechanistic basis for DDFTFS may facilitate the identification of pre- and on-treatment features, and therapeutic components and sequences, necessary to extend this ultimate therapeutic goal to a larger subset of patients. [Table: see text]

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]

TPS599 Background: Small cell bladder cancer (SCBC) is a rare aggressive bladder cancer (BC) variant comprising

Urothelial Cancer - Genomic Analysis to Improve Patient Outcomes and Research (NCT02643043), UC-GENOME, is a genomic analysis and biospecimen repository study in 218 patients with metastatic urothelial carcinoma. Here we report on the primary outcome of the UC-GENOME—the proportion of subjects who received next generation sequencing (NGS) with treatment options—and present the initial genomic analyses and clinical correlates. 69.3% of subjects had potential treatment options, however only 5.0% received therapy based on NGS. We found an increased frequency ofTP53E285Kmutations as compared to non-metastatic cohorts and identified features associated with benefit to chemotherapy and immune checkpoint inhibition, including: Ba/Sq and Stroma-rich subtypes, APOBEC mutational signature (SBS13), and inflamed tumor immune phenotype. Finally, we derive a computational model incorporating both genomic and clinical features predictive of immune checkpoint inhibitor response. Future work will utilize the biospecimens alongside these foundational analyses toward a better understanding of urothelial carcinoma biology.

The antibody-drug conjugate enfortumab-vedotin acts by targeting nectin-4, a protein that is nearly ubiquitously expressed in conventional urothelial cancer. However, expression of nectin-4 in morphologic variants of urothelial carcinoma and nonurothelial histotypes was unknown. Immunohistochemistry for nectin-4 using was performed on 169 patients including 83 with nonmuscle invasive bladder cancer and 86 patients with muscle invasive bladder cancer. Staining was scored for intensity (0 to 3) and extent (% positive cells) using the histological score system, where >15 was considered positive. Overall, 72/83 (87%) samples of nonmuscle invasive urothelial carcinoma were positive, including 29/30 (97%) noninvasive papillary urothelial carcinomas, 7/8 (87.5%) carcinomas in situ, 36/45 (80%) papillary urothelial carcinomas invading the lamina propria. Overall, 50/86 muscle invasive tumors were positive, including 15/22 (68.2%) urothelial carcinomas, 7/10 (70%) squamous cell carcinomas, 3/11 (28%) micropapillary tumors, 4/6 (66%) adenocarcinomas, 2/4 (50%) nested carcinomas, 5/8 (63%) plasmacytoid, 1/10 (10%) sarcomatoid carcinomas, and 0/15 (0%) small cell carcinomas. Whole transcriptome RNA sequencing revealed that compared with conventional urothelial carcinomas, most sarcomatoid carcinomas and all but 2 small cell carcinomas expressed very low levels of nectin-4 mRNA but expressed significant levels of either trop2 or ERBB2, which are the molecular targets of 2 other antibody-drug conjugates-sacituzumab gavitecan (trop2) or trastuzumab deruxtecan (ERBB2/HER2). In summary, our study demonstrates that there is heterogeneity of expression of nectin-4 in morphologic variants of urothelial cancer and nonurothelial histotypes, and suggests that testing expression of nectin-4 should be considered in morphologic variants or nonurothelial histotypes found to have lower expression.

INTRODUCTION AND OBJECTIVE:Muscle invasive bladder cancer (MIBC) surgical management has been historically a radical cystoprostatectomy in males and an anterior exenteration in females. Uterine and...

B cells have been implicated as central regulators of immune responses in settings as diverse as mammalian pregnancy, mucosal tolerance, chronic infection states, autoimmunity, and the tumor microenvironment. Despite the established importance of B cells in these environments, the mechanisms by which B cells are maintained in these contexts remain undefined. Here, we report that IDO1 pathway inhibition with D-1-methyl-tryptophan (D-1MT) and linrodostat significantly decreases tumor infiltrating B (TIL-B) cells in a preclinical model of melanoma. Single cell RNA sequencing (scRNAseq) of murine melanoma demonstrate TIL-B cells are heterogeneous but primarily express markers consistent with an immune stimulatory phenotype. D-1MT decreases splenic B cells and bone marrow derived B cell precursors in tumor-bearing mice, suggesting that IDO1 pathway inhibition impedes B cell maturation. D-1MT decreases intratumoral myeloid derived suppressor cells (MDSCs), which are essential for maintenance of TIL-B cells. Unlike D-1MT, genetic deletion of tumor Ido1 does not impact TIL-B or MDSC numbers. In human solid tumors, intratumoral IDO1 expression consistently associates with high expression of a pan-B cell gene signature, and in patients with melanoma, scRNAseq analysis of tumor samples revealed most TIL-B cells express IDO1. Collectively, our data reveal the impact of pharmacologic IDO1 inhibition on B cells, which may have therapeutic implications for patients with solid tumors by informing the design of future oncology clinical trials.

PURPOSE Locally advanced or metastatic urothelial carcinoma is an incurable disease with limited treatment options, especially for patients who were previously treated with platinum and anti–programmed death 1 or anti–programmed death ligand 1 (PD-1/L1) therapy. Enfortumab vedotin is an antibody–drug conjugate that targets Nectin-4, which is highly expressed in urothelial carcinoma. METHODS EV-201 is a global, phase II, single-arm study of enfortumab vedotin 1.25 mg/kg (intravenously on days 1, 8, and 15 of every 28-day cycle) in patients with locally advanced or metastatic urothelial carcinoma who were previously treated with platinum chemotherapy and anti–PD-1/L1 therapy. The primary end point was objective response rate per Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 by blinded independent central review. Key secondary end points were duration of response, progression-free survival, overall survival, safety, and tolerability. RESULTS Enfortumab vedotin was administered to 125 patients with metastatic urothelial carcinoma. Median follow-up was 10.2 months (range, 0.5 to 16.5 months). Confirmed objective response rate was 44% (95% CI, 35.1% to 53.2%), including 12% complete responses. Similar responses were observed in prespecified subgroups, such as those patients with liver metastases and those with no response to prior anti–PD-1/L1 therapy. Median duration of response was 7.6 months (range, 0.95 to 11.30+ months). The most common treatment-related adverse events were fatigue (50%), any peripheral neuropathy (50%), alopecia (49%), any rash (48%), decreased appetite (44%), and dysgeusia (40%). No single treatment-related adverse events grade 3 or greater occurred in 10% or more of patients. CONCLUSION Enfortumab vedotin demonstrated a clinically meaningful response rate with a manageable and tolerable safety profile in patients with locally advanced or metastatic urothelial carcinoma who were previously treated with platinum and anti–PD-1/L1 therapies.

Context The recent discovery of the existence of a human genitourinary microbiome has led to the investigation of its role in mediating the pathogenesis of genitourinary malignancies, including bladder, kidney, and prostate cancers. Furthermore, although it is largely recognized that members of the gastrointestinal microbiota are actively involved in drug metabolism, new studies demonstrate additional roles and the potential necessity of the gastrointestinal microbiota in dictating cancer treatment response. Objective To summarize the current evidence of a mechanistic role for the genitourinary and gastrointestinal microbiome in genitourinary cancer initiation and treatment response. Evidence acquisition We conducted a literature search up to October 2018. Search terms included microbiome, microbiota, urinary microbiome, bladder cancer, urothelial carcinoma, renal cell carcinoma, kidney cancer, testicular cancer, and prostate cancer. Evidence synthesis There is preliminary evidence to implicate the members of the genitourinary microbiota as causative factors or cofactors in genitourinary malignancy. Likewise, the current evidence for gastrointestinal microbes in dictating cancer treatment response is mainly correlative; however, we provide examples where therapeutic agents used for the treatment of genitourinary cancers are affected by the human-associated microbiota, or vice versa. Clinical trials, such as fecal microbiota transplant to increase the efficacy of immunotherapy, are currently underway. Conclusions The role of the microbiome in genitourinary cancer is an emerging field that merits further studies. Translating microbiome research into clinical action will require incorporation of microbiome surveillance into ongoing and future clinical trials as well as expansion of studies to include metagenomic sequencing and metabolomics. Patient summary This review covers recent evidence that microbial populations that reside in the genitourinary tract—and were previously not known to exist—may influence the development of genitourinary malignancies including bladder, kidney, and prostate cancers. Furthermore, microbial populations that exist at sites outside of the genitourinary tract, such as those that reside in our gut, may influence cancer development and/or treatment response.

Non-muscle invasive bladder cancer is marked by frequent recurrences and a risk for progression to life threatening disease. Intravesical Bacillus Calmette-Guerin (BCG), one of the earliest effective immunotherapies for cancer, remains the current standard for treating high-risk non-muscle invasive bladder cancer. Optimal treatment with BCG includes periodic 3 weekly maintenance instillations, often with dose reduction to minimize toxicity. However, despite its efficacy, treatment failure is common. Efforts to provide alternate and potentially more effective therapy for this disease include increased understanding of bladder cancer through molecular profiling, multi-agent intravesical chemotherapy, and novel forms of immunotherapy.

TPS4617 Background: Patients [pts] withlymph node positive (LN+), non-metastatic bladder cancer (BC) have a better prognosis than those with metastatic (M1) disease. However, this population is under-represented in advanced bladder trials and ineligible for bladder-sparing trials. Therefore, there have been no larger prospective trials establishing the standard of care in LN+ BC. Given the promise of immunotherapy in advanced BC and potential synergy between immunotherapy and radiation, INSPIRE was designed to determine the role of concurrent and adjuvant durvalumab (durva) in this patient population when treated with induction chemotherapy (IC) followed by concurrent chemoRT. Methods: This is a randomized phase II study that is enrolling BC pts with stage III [N1-3 M0], pure or mixed urothelial cancer. Pts must have received ≥3 cycles of IC [either before or after registration, prior to randomization] without progression. LN+ is defined as radiologically LN ≥1.0 cm in short axis, with or without biopsy prior to IC. As long as pts do not progress on induction chemotherapy, they will be randomized to chemoRT+/- durva using 5 stratification factors (Simon Pocock minimization method) a) IC prior vs. post registration b) cisplatin vs non-cisplatin regimen during RT c) LN size d) response to IC e) extent of TURBT. Pts on the chemoRT+durva arm will get chemotherapy per physician choice + IMRT + 3 x doses of Q3wk durva for 6.5-8 wks, whereas those on the control arm will get chemoRT alone. The primary end point is clinical complete response [CR], defined as no radiologically measurable disease in the LNs and negative cystoscopy and bladder biopsy 8-10 weeks post-chemoRT +/- durva. Pts on the chemoRT + durva arm who have a CR or clinical benefit ( > T0 and ≤T2 in bladder per cystoscopy, biopsy + CR/PR/SD in LN by imaging) will get adjuvant Q4wk durva for 9 doses, while those on the chemoRT arm will undergo observation. Secondary end points include OS, PFS, bladder-intact event-free survival, rate of toxicity and salvage cystectomy. This study is designed to detect an improvement of 25% in clinical CR between both arms (37.5% to 62.5%). A total accrual of 114 pts (in order to enroll 92 evaluable pts) will provide 81% power to detect this difference using a Fisher’s exact test (assuming 10% drop out + anticipating that 20% chemotherapy-naïve pts will progress post IC). We are banking blood and primary tumor tissue pre- and post-chemoRT in both groups. The study was activated in August 2020 and accrual is ongoing. We expanded eligibility to include N3 in 9/2021. INSPIRE is the first prospective study designed for only LN+ BC and will define both short-term and long-term outcomes for bladder sparing in this patient population and has the potential to define a new treatment strategy for stage III BC. Clinical trial information: NCT04216290.

4561 Background: Frontline cisplatin-based chemotherapy improves survival in patients (pts) with UC, but ̃50% are cisplatin-ineligible owing to poor performance status or comorbidity. The definition of platinum ineligibility is not standardized; hence, treatment decisions are almost solely made by clinical judgment. Pembrolizumab (pembro) showed antitumor activity and manageable toxicity as frontline therapy in 370 cisplatin-ineligible pts in the single arm, phase 2 KEYNOTE-052 trial (NCT02335424). We present effects of pembro on HRQoL of pts in KEYNOTE-052 who were potentially platinum ineligible in this exploratory analysis. Methods: Eligible pts for KEYNOTE-052 were adults with no prior systemic chemotherapy for advanced/metastatic UC, ECOG PS ≤2, and measurable disease per RECIST v1.1 by blinded independent central review. Pembro 200 mg IV was administered Q3W for up to 2 y. Clinical characteristics of frail pts (platinum ineligible) were identified by extensive review of real-world treatment patterns and relevant literature. Consequently, platinum ineligibility was defined as having an ECOG PS ≥2 plus ≥1 of the following: visceral disease, creatinine clearance < 60 mL/min, or age ≥80 y. HRQoL was assessed using the EORTC QLQ-C30 and EQ-5D-3L during the first 4 cycles, then every 2 cycles for 1 year or until treatment discontinuation (whichever occurred first), and at least 30 days after treatment discontinuation. Key end points were change from baseline per the QLQ-C30 global health status (GHS)/QoL score, QLQ-C30 physical functioning subscale, and EQ-5D visual analog scale (VAS). The minimum important difference (MID) was 10 for QLQ-C30 score change (improved: ≥10; stable: –10 to 10; deteriorated: –10 or less); MID for VAS score change was 7 (improved: ≥7; stable: –7 to 7; deteriorated: –7 or less). Results: Median age for 143 pts was 75 y (range, 34-91); 129 pts (90.2%) had visceral disease; 142 (99.3%) had ECOG PS 2; 1 had ECOG PS 3 (enrolled in error). Compliance rate for HRQoL questionnaires was 93.7% at baseline. At the prespecified analysis time of week 9, 77.6% of pts had improved (n = 51) or stable (n = 60) QLQ-C30 GHS/QoL scores, 64.3% had improved (n = 35) or stable (n = 57) QLQ-C30 physical functioning scores, and 62.2% had improved (n = 56) or stable (n = 33) EQ-5D VAS scores. These scores were stable throughout the HRQoL assessment period for pts who continued pembro. Conclusions: In this exploratory analysis, pembro maintained HRQoL for pts with advanced/metastatic UC in KEYNOTE-052 who were potentially platinum-ineligible per the above criteria. Together with the efficacy and safety data from KEYNOTE-052, these data suggest that pembro monotherapy is a valuable treatment option for select pts with advanced UC who are more senior and/or deemed medically frail. Clinical trial information: NCT02335424.

5081 Background: To date there is no prospective survival data beyond 5 years for patients treated with ADT with or without docetaxel (D) when analyzed by well-defined baseline prognostic risk groups and treatment arms. In this updated analysis of the CHAARTED trial, we report the 8-year survival rate based on disease volume and metachronous vs. de novo metastatic disease status with ADT without or with docetaxel. Methods: An updated survival sweep was conducted in February 2022. Patients were prospectively identified by the state of metastatic disease as metachronous (prior local therapy) vs. de novo and low volume (LV) vs. high volume (HV; visceral and/or ≥4 bone metastases with one lesion beyond the vertebral bodies or pelvis) disease. Overall survival (OS) was defined as time from randomization to death or date last known alive and calculated using the Kaplan-Meier method. Results: Of the 790 patients randomized (last patient enrolled December 2012), 238 patients were still alive with a median follow up of 9.7 years for patients still alive. Median OS in the overall population was 60.4 and 47.2 mos in the ADT+ D and ADT arms respectively (Table; HR: 0.77; 95% CI: 0.65, 0.92; p=0.004). ADT+ D was associated with significantly higher 8-yr OS rate (28.5%) compared to ADT arm (15.4%; HR: 0.67; 95% CI: 0.53, 0.84; p=0.0005) in the de novo HV group (n=421). Notably, the 8-yr OS rates were almost doubled for patients with HV disease with early docetaxel (16% vs.30.2%, p

Background The authors evaluated mocetinostat (a class I/IV histone deacetylase inhibitor) in patients with urothelial carcinoma harboring inactivating mutations or deletions in CREB binding protein [CREBBP] and/or E1A binding protein p300 [EP300] histone acetyltransferase genes in a single‐arm, open‐label phase 2 study. Methods Eligible patients with platinum‐treated, advanced/metastatic disease received oral mocetinostat (at a dose of 70 mg 3 times per week [TIW] escalating to 90 mg TIW) in 28‐day cycles in a 3‐stage study (ClinicalTrials.gov identifier NCT02236195). The primary endpoint was the objective response rate. Results Genomic testing was feasible in 155 of 175 patients (89%). Qualifying tumor mutations were CREBBP (15%), EP300 (8%), and both CREBBP and EP300 (1%). A total of 17 patients were enrolled into stage 1 (the intent‐to‐treat population); no patients were enrolled in subsequent stages. One partial response was observed (11% [1 of 9 patients; the population that was evaluable for efficacy comprised 9 of the 15 planned patients]); activity was deemed insufficient to progress to stage 2 (null hypothesis: objective response rate of ≤15%). All patients experienced ≥1 adverse event, most commonly nausea (13 of 17 patients; 77%) and fatigue (12 of 17 patients; 71%). The median duration of treatment was 46 days; treatment interruptions (14 of 17 patients; 82%) and dose reductions (5 of 17 patients; 29%) were common. Mocetinostat exposure was lower than anticipated (dose‐normalized maximum serum concentration [Cmax] after TIW dosing of 0.2 ng/mL/mg). Conclusions To the authors’ knowledge, the current study represents the first clinical trial using genomic‐based selection to identify patients with urothelial cancer who are likely to benefit from selective histone deacetylase inhibition. Mocetinostat was associated with significant toxicities that impacted drug exposure and may have contributed to modest clinical activity in these pretreated patients. The efficacy observed was considered insufficient to warrant further investigation of mocetinostat as a single agent in this setting., After the genomic‐based selection of patients with urothelial cancer with inactivating mutations/deletions in the histone acetyltransferase genes CREBBP and/or EP300, single‐agent mocetinostat appears to be associated with significant toxicities that limit drug exposure. This may have contributed to the limited activity noted in the current phase 2 study (response rate of 11%) among heavily pretreated patients with platinum‐refractory disease.

Background There is a great need to identify biomarkers that can accurately identify patients who will obtain the most clinical benefit from immune checkpoint inhibitor (ICI) therapy. While high intratumoral B cell gene expression correlated with an ICI response in melanoma, whether it adds predictive value in other cancers is unknown. Objective To examine the relationship between B cell gene signature (BCGS) expression and overall survival (OS) following ICI treatment. Design, setting, and participants A total of 348 patients with advanced urothelial carcinoma from the IMvigor 210 phase 2 clinical trial of atezolizumab and 406 patients with muscle-invasive bladder cancer from The Cancer Genome Atlas (TCGA) were included. Outcome measurements and statistical analysis We analyzed tumor RNA sequencing data of included patients to examine the relationships between a BCGS and clinical outcomes. Results and limitations Tumors with high levels of B cell and CD8+ T cell gene signatures (BCGS/CD8TGS or B8T high/high) were associated with the longest OS of all B8T groups. Moreover, the B8T cell signature stratified patients whose tumors had a high tumor mutational burden or high programmed death ligand 1 (PD-L1) into subsets with differential OS outcomes. Whereas the B8T high/high tumors were associated with the best clinical outcomes in ICI-treated men, they were not associated with better OS in women. Conversely, women with B8T high/high tumors had the best clinical outcomes in non–ICI-treated muscle-invasive bladder cancer. Conclusions These data suggest that the B8T signature can enhance OS stratification in patients with advanced urothelial carcinoma who are treated with ICI therapy and that sex-specific differences in the tumor immune microenvironment may drive disparate outcomes. Patient summary We examined whether the presence of two immune cell gene signatures within tumor samples impact survival in patients with bladder cancer. High levels of both of these signatures (B cells and CD8+ T cells) associate with superior survival in patients who receive immune therapy.

PURPOSE: A prognostic model for overall survival of post-platinum patients with metastatic urothelial carcinoma receiving PD-1/PD-L1 inhibitors is necessary as existing models were constructed in the chemotherapy setting. MATERIALS AND METHODS: Patient level data were used from phase I/II trials evaluating PD-L1 inhibitors following platinum based chemotherapy for metastatic urothelial carcinoma. The derivation data set consisted of 2 phase I/II trials evaluating atezolizumab (405). Two phase I/II trials that evaluated avelumab (242) and durvalumab (198) comprised the validation data sets. Cox regression analyses evaluated the association of candidate prognostic factors with overall survival. Stepwise selection was used to select an optimal model using the derivation data set. Discrimination and calibration were assessed in the avelumab and durvalumab data sets. RESULTS: The 5 prognostic factors identified in the optimal model using the atezolizumab derivation data set were ECOG-PS (1 vs 0, HR 1.80, 95% CI 1.36-2.36), liver metastasis (HR 1.55, 95% CI 1.20-2.00), platelet count (HR 2.22; 95% CI 1.54-3.18), neutrophil-to-lymphocyte ratio (HR 1.94, 95% CI 1.57-2.40) and lactate dehydrogenase (HR 1.60, 95% CI 1.28-1.99). There was robust discrimination of survival between low, intermediate and high risk groups. The c-statistic was 0.692 in the derivation and 0.671 and 0.773 in the avelumab and durvalumab validation data sets, respectively. A web based interactive tool was developed to calculate the expected survival probabilities based on risk factors. CONCLUSIONS: A validated 5-factor model has satisfactory prognostic performance for survival across 3 PD-L1 inhibitors to treat metastatic urothelial carcinoma after platinum therapy and may assist in stratification, interpreting and designing trials incorporating PD-1/PD-L1 inhibitors in the post-platinum setting.

Recent advances in surgical techniques, bladder cancer molecular biology discoveries, access to point-of-care genomic biomarker platforms, and therapy options in metastatic bladder cancer patients suggest that significant improvements in the options and outcomes for patients with muscle-invasive bladder cancer (MIBC) are achievable. Indeed, multiple MIBC clinical trials with practice-changing impact are ongoing. This chapter provides a synopsis of the key populations, designs, and endpoints under investigation in these important MIBC trials.

Background Treatment options have been historically limited for cisplatin-ineligible patients with advanced urothelial carcinoma (UC). Given the need for alternatives to platinum-based chemotherapy, including non-chemotherapy regimens for patients with both impaired renal function and borderline functional status, in 2010 (prior to the immune checkpoint blockade era in metastatic UC), we initiated a phase II trial to test the activity of everolimus or everolimus plus paclitaxel in the cisplatin-ineligible setting. Methods This was an open-label phase II trial conducted within the US-based Hoosier Cancer Research Network (ClinicalTrials.gov number: NCT01215136). Patients who were cisplatin-ineligible with previously untreated advanced UC were enrolled. Patients with both impaired renal function and poor performance status were enrolled into cohort 1; patients with either were enrolled into cohort 2. Patients received everolimus 10 mg daily alone (cohort 1) or with paclitaxel 80 mg/m2 on days 1, 8, and 15 of each 28-day cycle (cohort 2). The primary outcome was clinical benefit at 4 months. Secondary outcomes were adverse events, progression-free survival (PFS), and 1-year overall survival (OS). Exploratory endpoints included genomic correlates of outcomes. The trial was not designed for comparison between cohorts. Results A total of 36 patients were enrolled from 2010 to 2018 (cohort 1, N = 7; cohort 2, N = 29); the trial was terminated due to slow accrual. Clinical benefit at 4 months was attained by 0 (0%, 95% confidence interval [CI] 0-41.0%) patients in cohort 1 and 11 patients (37.9%, 95% CI 20.7-57.7%) in cohort 2. Median PFS was 2.33 (95% CI 1.81-Inf) months in cohort 1 and 5.85 (95% CI 2.99-8.61) months in cohort 2. Treatment was discontinued due to adverse events for 2 patients (29%) in cohort 1 and 11 patients (38%) in cohort 2. Molecular alterations in microtubule associated genes may be associated with treatment benefit but this requires further testing. Conclusion Everolimus plus paclitaxel demonstrates clinical activity in cisplatin-ineligible patients with metastatic UC, although the specific contribution of everolimus cannot be delineated. Patients with both impaired renal function and borderline functional status may be difficult to enroll to prospective trials. (ClinicalTrials.gov Identifier NCT01215136).

Introduction Small cell subtype is a rare and aggressive variant of bladder and upper tract cancers. Due to poor prognosis, patients with any component of this variant are often excluded from clinical trials, thus activity of novel agents in this population is unknown. Patients and Methods We retrospectively reviewed the Johns Hopkins Greenberg Bladder Cancer Center’s database of patients with small cell variant bladder and upper tract cancer treated with checkpoint inhibitors in the second line and beyond between 2014 – 2019. Results Out of 5 identified patients, 3 demonstrated radiographic response. Toxicity of checkpoint inhibitor therapy post platinum was similar to that described in conventional urothelial cancer. Incidence of TP53 and RB alterations were high in this group, as has been previously reported with this subtype. Conclusion Our series indicates small cell variant bladder cancers are sensitive to checkpoint inhibitor immunotherapy. Inclusion, rather than exclusion of patients with variant subtype histology to clinical trials with novel agents, will better serve patients with historically poorer prognosis than those with conventional urothelial cancer.

Background: While immune checkpoint inhibitors (ICIs) are approved in the first-line (1L) setting for cisplatin-unfit patients with programmed death-ligand 1 (PD-L1)-high tumors or for platinum (cisplatin/carboplatin)-unfit patients, response rates remain modest and outcomes vary with no clinically useful biomarkers (except for PD-L1). Objective: We aimed to develop a prognostic model for overall survival (OS) in patients receiving 1L ICIs for advanced urothelial cancer (aUC) in a multicenter cohort study. Design, setting, and participants: Patients treated with 1L ICIs for aUC across 24 institutions and five countries (in the USA and Europe) outside clinical trials were included in this study. Outcome measurements and statistical analysis: We used a stepwise, hypothesis-driven approach using clinician- selected covariates to develop a new risk score for patients receiving ICIs in the 1L setting. Demographics, clinicopathologic data, treatment patterns, and OS were collected uniformly. Univariate Cox regression was performed on 18 covariates hypothesized to be associated with OS based on published data. Variables were retained for multivariate analysis (MVA) if they correlated with OS (p < 0.2) and were included in the final model if p < 0.05 on MVA. Retained covariates were assigned points based on the beta coefficient to create a risk score. Stratified median OS and C- statistic were calculated. Results and limitations: Among 984 patients, 357 with a mean age of 71 yr were included in the analysis, 27% were female, 68% had pure UC, and 13% had upper tract UC. Eastern Cooperative Oncology Group performance status ≥2, albumin 5, and liver metastases were significant prognostic factors on MVA and were included in the risk score. C index for new 1L risk score was 0.68 (95% confidence interval 0.65-0.71). Limitations include retrospective nature and lack of external validation. Conclusions: We developed a new 1L ICI risk score for OS based on data from patients with aUC treated with ICIs in the USA and Europe outside of clinical trials. The score components highlight readily available factors related to tumor biology and treatment response. External validation is being pursued. Patient summary: With multiple new treatments under development and approved for advanced urothelial carcinoma, it can be difficult to identify the best treatment sequence for each patient. The risk score may help inform treatment discussions and estimate outcomes in patients treated with first-line immune checkpoint inhibitors, while it can also impact clinical trial design and endpoints. TAKE HOME MESSAGE: A new risk score was developed for advanced urothelial carcinoma treated with first- line immune checkpoint inhibitors. The score assigned Eastern Cooperative Oncology Group performance status ≥2, albumin 5, and liver metastases each one point, with a higher score being associated with worse overall survival.

VEGF blockade does not uniformly result in clinical benefit. We evaluated safety, dose-limiting toxicities (DLT), recommended phase II dose (RP2D), antitumor efficacy, and exploratory biomarkers including pharmacogenomics and pharmacokinetics with sorafenib, bevacizumab, and paclitaxel in patients with refractory cancers. The study had a “3 + 3” design, using paclitaxel 80 mg/m2 every week for 3 weeks, in every 4 week cycles, bevacizumab 5 mg/kg every 2 weeks, and sorafenib 200 or 400 mg twice a day, 5 or 7 days/week (5/7, 7/7). The MTD cohort was expanded. Twenty-seven patients enrolled in 3 cohorts: sorafenib 200 mg twice a day 5/7, 200 mg twice a day 7/7, and 400 mg twice a day 5/7. DLTs were grade 3 neutropenia >7 days (cohort 1, 1), grade 3 hypertension (cohort 2, 1), grade 3 hand–foot skin reaction (HFSR; cohort 3, 2). MTD was sorafenib 200 mg twice a day 7/7. Six DLTs occurred in cohort 2 expansion: grade 3 HFSR (2), grade 2 HFSR with sorafenib delay >7 days (2), grade 4 cerebrovascular accident (1), grade 3 neutropenia >7 days (1). RP2D was sorafenib 200 mg twice a day 5/7. Most patients (62%) dose reduced sorafenib to 200 mg daily 5/7 after a median 3 (range, 2–17) cycles. Response rates were 48% overall (27) and 64% for ovarian cancers (14). VEGF-A-1154AA and -7TT recessive homozygous genotypes conferred worse overall survival versus alternative genotypes (7 vs. 22 months). Intermittent, low-dose sorafenib (200 mg twice a day 5/7) combined with bevacizumab and paclitaxel was tolerable and had high antitumor efficacy in patients with refractory cancer (NCT00572078).

INTRODUCTION AND OBJECTIVE:Sarcomatoid urothelial carcinoma (SUC) is an unusual variant that bears poor prognosis. Guidelines recommend consideration for early radical cystectomy (RC) in patients w...

INTRODUCTION AND OBJECTIVE:The standard of care for eligible patients with muscle-invasive bladder cancer (MIBC) includes neoadjuvant cisplatin-based chemotherapy (NAC), followed by radical cystect...

INTRODUCTION AND OBJECTIVE:Small cell bladder carcinoma (SCBC) is clinically-aggressive variant of urothelial carcinoma with advanced stage at presentation. Due to its rarity, its molecular charact...

INTRODUCTION AND OBJECTIVE:Metastatic recurrence (MR) of upper tract urothelial carcinoma (UTUC) occurs in over 25% of patients treated with radical nephroureterectomy (RNU). While MR suggests poor...

493 Background: Standard treatment (tx) for high-risk NMIBC is transurethral resection of bladder tumor (TURBT) followed by BCG induction and maintenance. However, ≈50% of pts experience recurrence and/or progression after tx and may be ineligible for or refuse cystectomy. The PD-L1/PD-1 pathway may be involved with immune escape in NMIBC following BCG exposure. Here, we report results of atezo (anti–PD-L1) ± BCG in BCG-unresponsive, high-risk NMIBC. Methods: This multicenter study (NCT02792192) enrolled pts with BCG-unresponsive NMIBC with carcinoma in situ who had repeat TURBT. Cohort 1A and 1B pts received atezo 1200 mg IV q3w for ≤96 wk. Cohort 1B pts also received standard BCG induction (qw × 6 doses) and maintenance (qw × 3 doses at 3 mo), with optional maintenance courses at 6, 12, 18, 24, and 30 mo. For cohort 1B only, de-escalation was allowed for ≤3 BCG dose levels (full dose 50 mg, 66% and 33% of full dose). Co-primary outcomes were safety and complete response (CR) rate at 6 mo (6-mo bladder biopsy required). Duration of CR and 3-mo CR rate (key secondary outcomes) and 12-mo CR rate (exploratory) were also shown. Results: Cohorts 1A and 1B enrolled 12 pts each. Median age was 74 y; most pts had ECOG PS 0 (n = 7 [58%] in each cohort). At data cutoff (Sep 29, 2020), median atezo tx duration was 22.7 wk in cohort 1A and 31.6 wk in 1B. Following dose de-escalation in cohort 1B, the recommended BCG dose was 50 mg. BCG dose modification/interruption occurred in 4 pts (33%) due to an AE. The most common reason for tx discontinuation was disease recurrence or progression in both cohorts. Three pts (25%) in cohort 1A had atezo-related Gr 3 AEs (most common: maculopapular rash, n = 2); no atezo- or BCG-related Gr ≥3 AEs were seen in cohort 1B. Three dose-limiting toxicities occurred (1 [8%] in cohort 1A and 2 [17%] in cohort 1B), all reported as AEs of special interest. No Gr 4/5 AEs were reported. CRs, which appeared durable, were seen in both cohorts (Table). Conclusions: In this first report of atezo + BCG in NMIBC, atezo as mono- and combination therapy was well tolerated, with no new safety signals or tx-related deaths. Preliminary data suggested clinically meaningful activity, especially with atezo + BCG, requiring confirmation in a larger setting. Clinical trial information: NCT02792192. [Table: see text]

TPS597 Background: Cohort A of the phase 2 KEYNOTE-057 study showed that pembrolizumab monotherapy provided effective antitumor activity and acceptable safety in patients with BCG-unresponsive HR NMIBC with carcinoma in situ (CIS). Pembrolizumab in combination with BCG at earlier stages of HR NMIBC might provide benefit superior to that of BCG monotherapy. The open-label, comparator-controlled, phase 3 KEYNOTE-676 study (NCT03711032) will be conducted to investigate the efficacy and safety of pembrolizumab + BCG versus BCG monotherapy in patients with HR NMIBC. Cohort A will enroll patients with persistent or recurrent HR NMIBC after BCG induction. Cohort B is a new, randomly assigned cohort that will help evaluate pembrolizumab + BCG in BCG treatment–naive patients who either never received BCG treatment or received BCG treatment > 2 years before enrollment. Methods: Cohort B of KEYNOTE-676 will enroll approximately 975 patients with blinded independent central review (BICR)–confirmed HR NMIBC (T1, high-grade Ta CIS) and Eastern Cooperative Oncology Group performance status score 0-2 who underwent cystoscopy/transurethral resection of bladder tumor ≤12 weeks before randomization and had not received BCG within the past 2 years. Patients will be randomly assigned 1:1:1 to receive pembrolizumab 400 mg intravenously (IV) every 6 weeks (Q6W) + BCG reduced maintenance (≤6 months), pembrolizumab 400 mg IV Q6W + BCG full maintenance (≤18 months), or BCG monotherapy (BCG full maintenance). Stratification factors include NMIBC stage (CIS or no CIS) and PD-L1 expression (combined positive score [CPS] ≥10 or CPS < 10), determined by central laboratory. Disease status will be assessed by use of cystoscopy, urine cytology, and biopsy (as applicable) every 12 weeks (Q12W) through year 2, then every 24 weeks through year 5; imaging with computed tomography urography will occur every 72 weeks. Adverse events (AEs) will be monitored throughout the study and up to 30 days after cessation of study treatment (90 days for serious AEs). The primary end point is event-free survival (EFS). Secondary end points include complete response rate by BICR, duration of response (DOR), 12-month DOR rate (CIS only), 24-month EFS rate, disease-specific survival, time to cystectomy, overall survival, and safety. The study is enrolling or planning to enroll at sites in Asia, Australia, Europe, North America, and South America. Clinical trial information: NCT03711032.

512 Background: Pembrolizumab (pembro) has shown efficacy in advanced/unresectable and metastatic UC (mUC). There is interest in determining whether pts should be treated subsequently with checkpoint inhibitors such as anti–PD-1 therapy if mUC responds then later progresses. Pembro retreatment after disease progression has shown efficacy in melanoma and NSCLC. This post hoc exploratory analysis investigated the efficacy of pembro retreatment for pts with advanced UC or mUC enrolled in KEYNOTE-045 and KEYNOTE-052 with a best overall response (BOR) of SD or better and whose disease progressed after discontinuation or completion of 2 y of therapy. Methods: The phase 3 KEYNOTE-045 trial (NCT02256436) was designed to compare the efficacy and safety of pembro vs chemotherapy (chemo) in pts with mUC that recurred/progressed on platinum containing chemo; ≤2 prior lines of systemic chemo for mUC were permitted. The phase 2 KEYNOTE-052 trial (NCT02335424) was designed to evaluate the efficacy and safety of first-line pembro in cisplatin-ineligible pts with advanced UC. In both studies, pembro was administered for up to 2 y; pts were eligible for retreatment if they stopped pembro after CR or had a BOR of CR, PR, or SD and completed 2 y of treatment. Pts must have investigator-confirmed radiographic PD after therapy cessation, have ECOG PS score 0-1, and not have received anticancer treatment after the last pembro dose. BOR to retreatment is reported. Results: At data cutoff for KEYNOTE-045 (Oct 1, 2020), 11 pts were retreated: 5 (45%) achieved objective response to retreatment (3 CR; 2 PR; Table) and 6 had SD, for a disease control rate (DCR; CR+PR+SD) of 100%. Median treatment-free interval was 7.7 mo (IQR, 3.6-16.5); median duration of retreatment was 11.4 mo (IQR, 7.6-12.0). Seven pts (64%) were alive at cutoff. At data cutoff for KEYNOTE-052 (Sep 26, 2020), 10 pts were retreated; 5 (50%) had objective response to retreatment (1 CR; 4 PR) and 4 had SD, for a DCR of 90%. Retreatment BOR was PD for 1 pt (10%). Median treatment-free interval was 13.0 mo (9.2-16.6); median duration of retreatment was 6.0 mo (IQR, 4.9-9.2). Four pts (40%) were alive at cutoff. Conclusions: Although the number of pts who received retreatment was small, objective responses were observed. The findings are generally consistent with observations from retreatment in other tumor types (e.g., melanoma). Clinical trial information: NCT02256436 and NCT02335424. [Table: see text]

521 Background: First-line treatment with pembrolizumab (pembro) monotherapy has shown durable clinical activity in selected patients (pts) with advanced/unresectable or metastatic urothelial carcinoma (UC). In a pooled population of pts with advanced UC from the single-arm phase 2 KEYNOTE-052 (NCT02335424) and the randomized, open-label, phase 3 KEYNOTE-361 (NCT02853305) studies, this exploratory analysis evaluated the relationship between baseline characteristics and clinical outcomes of first-line pembro monotherapy. Methods: Cisplatin-ineligible pts with advanced UC were enrolled in KEYNOTE-052 and chemotherapy-naive pts with advanced UC were enrolled in KEYNOTE-361. For analysis of predictive factors for ORR and OS in pembro-treated pts, the purposeful selection method was used to build the multivariable logistic regression model (ORR) and multivariable Cox model (OS), beginning with a univariable analysis of each independent variable. Any variable in the univariate model with P < 0.10 was a candidate for the multivariate model. The stepwise selection method was used to select the variables in the final model. Significance of the final model was set at P < 0.05. Data cutoff dates were September 26, 2020 (KEYNOTE-052) and April 29, 2020 (KEYNOTE-361). Results: This pooled analysis included 681 pts treated with pembro monotherapy (KEYNOTE-052, N = 374; KEYNOTE-361, N = 307 [170 were cisplatin ineligible]). Median follow-up was 51.9 mo (range, 22.0-65.3). ORR was 29.4% (95% CI, 26.0-32.9; 69 CRs, 131 PRs), and median DOR was 33.2 mo (range, 1.4+ to 60.7+). Median OS was 12.5 mo (95% CI, 11.0-14.6). By multivariate analysis, independent factors significantly associated with higher ORR were PD-L1 status (combined positive score [CPS] ≥10 vs CPS < 10; odds ratio [OR], 1.90 [95% CI, 1.33-2.71]; P = 0.0004), site of metastasis (lymph node only vs visceral disease; OR, 1.66 [95% CI, 1.06-2.59]; P = 0.0265), liver involvement (absent vs present; OR, 1.75 [95% CI, 1.06-2.89]; P = 0.0294), and baseline hemoglobin level ≥10 vs < 10 g/dL; OR, 2.17 [95% CI, 1.09-4.31]; P = 0.0276). Multivariate analysis of OS is displayed in the Table. Conclusions: This exploratory multivariate analysis identified numerous factors, including PD-L1–positive status (CPS ≥10), lymph node only metastasis, and lower ECOG PS score, associated with improved clinical outcomes in pts with advanced UC treated with first-line pembro monotherapy. Clinical trial information: NCT02335424 and NCT02853305. [Table: see text]

The SIU (Société Internationale d’Urologie)–ICUD (International Consultation on Urologic Diseases) working group on systemic therapy for metastatic bladder cancer has summarized the most recent findings on the aforementioned topic and came to conclusions and recommendations according to the evidence published. In Europe and the United States, treatment for metastatic UC has changed a great deal recently, mainly involving a move from chemotherapy to immune checkpoint blockers. This is particularly true in platinum-refractory disease, where supportive randomized data exist. Five checkpoint blockers have been approved in this setting by the FDA: avelumab, atezolizumab, durvalumab, nivolumab, and pembrolizumab. Nivolumab, pembrolizumab, and atezolizumab have been approved in Europe.

BACKGROUND Immune checkpoint inhibitors (ICIs) represent an appealing treatment for patients with advanced urothelial cancer (aUC) and a poor performance status (PS). However, the benefit of ICIs for patients with a poor PS remains unknown. It was hypothesized that a poor Eastern Cooperative Oncology Group (ECOG) PS (≥2 vs 0-1) would correlate with shorter overall survival (OS) in patients receiving ICIs. METHODS In this retrospective cohort study, clinicopathologic, treatment, and outcome data were collected for patients with aUC who were treated with ICIs at 18 institutions (2013-2019). The overall response rate (ORR) and OS were compared for patients with an ECOG PS of 0 to 1 and patients with an ECOG PS ≥ 2 at ICI initiation. The association between a new ICI in the last 30 and 90 days of life (DOL) and death location was also tested. RESULTS Of the 519 patients treated with ICIs, 395 and 384 were included in OS and ORR analyses, respectively, with 26% and 24% having a PS ≥ 2. OS was higher in those with a PS of 0 to 1 than those with a PS ≥ 2 who were treated in the first line (median, 15.2 vs 7.2 months; hazard ratio [HR], 0.62; P = .01) but not in subsequent lines (median, 9.8 vs 8.2 months; HR, 0.78; P = .27). ORRs were similar for patients with a PS of 0 to 1 and patients with a PS ≥ 2 in both lines. Of the 288 patients who died, 10% and 32% started ICIs in the last 30 and 90 DOL, respectively. ICI initiation in the last 30 DOL was associated with increased odds of death in a hospital (odds ratio, 2.89; P = .04). CONCLUSIONS Despite comparable ORRs, ICIs may not overcome the negative prognostic role of a poor PS, particularly in the first-line setting, and the initiation of ICIs in the last 30 DOL was associated with hospital death location.

Purpose: High risk upper tract urothelial carcinoma has been associated with poor survival outcomes. Limited retrospective data support neoadjuvant chemotherapy prior to radical nephroureterectomy. To validate prior findings we evaluated differences in the pathological stage distribution in patients with high risk upper tract urothelial carcinoma based on the administration of neoadjuvant chemotherapy before radical nephroureterectomy.Materials and Methods: We retrospectively analyzed the records of 240 patients with upper tract urothelial carcinoma at The Johns Hopkins Hospital from 2003 to 2017. Patients with biopsy proven high grade disease and a visible lesion on cross-sectional imaging were offered neoadjuvant chemotherapy prior to radical nephroureterectomy. A control group of a time matched cohort of patients with biopsy proven high grade disease underwent extirpative surgery alone. The chi-square and Fisher exact tests were used to evaluate clinical and pathological variables between the cohorts.R...

Overcoming acquired drug resistance remains a core challenge in the clinical management of human cancer, including in urothelial carcinoma of the bladder (UCB). Cancer stem-like cells (CSC) have been implicated in the emergence of drug resistance but mechanisms and intervention points are not completely understood. Here, we report that the proinflammatory COX2/PGE2 pathway and the YAP1 growth-regulatory pathway cooperate to recruit the stem cell factor SOX2 in expanding and sustaining the accumulation of urothelial CSCs. Mechanistically, COX2/PGE2 signaling induced promoter methylation of let-7, resulting in its downregulation and subsequent SOX2 upregulation. YAP1 induced SOX2 expression more directly by binding its enhancer region. In UCB clinical specimens, positive correlations in the expression of SOX2, COX2, and YAP1 were observed, with coexpression of COX2 and YAP1 particularly commonly observed. Additional investigations suggested that activation of the COX2/PGE2 and YAP1 pathways also promoted acquired resistance to EGFR inhibitors in basal-type UCB. In a mouse xenograft model of UCB, dual inhibition of COX2 and YAP1 elicited a long-lasting therapeutic response by limiting CSC expansion after chemotherapy and EGFR inhibition. Our findings provide a preclinical rationale to target these pathways concurrently with systemic chemotherapy as a strategy to improve the clinical management of UCB. Significance: These findings offer a preclinical rationale to target the COX2 and YAP1 pathways concurrently with systemic chemotherapy to improve the clinical management of UCB, based on evidence that these two pathways expand cancer stem-like cell populations that mediate resistance to chemotherapy. Cancer Res; 78(1); 168–81. ©2017 AACR.

Introduction Most carcinoma in-situ (CIS) molecular investigations to date have studied CIS in the context of concurrent papillary (Pap) tumors (conPap). A critical gap remains in our understanding of unique CIS biology. We investigated the feasibility of obtaining high-quality transcriptome data from CIS specimens utilizing the novel extraction-free EdgeSeq Precision Immuno-Oncology Panel (PIP) platform. Methods Formalin-fixed paraffin embedded CIS, CIS with conPap, and pure Pap tumors were identified. Tumor cells were macro-dissected from two unstained 5-micron thick slides and analyzed on the PIP panel comprised of 1,410 immunomodulatory genes. Principle components analyses (PCA) were performed to identify distinct cohorts. The Bioconductor DEseq2 package was used to identify differential gene expression between CIS +/- conPap and pure Pap tumors. Functional and pathway analyses were performed using Ingenuity Pathway Analysis software. Secondary analyses assessed any confounding effects of relevant patient clinical features. Results 135 specimens were identified including: 51 CIS (32 CIS, 19 CIS + concurrent high grade (HG) Ta-T2), 55 HG Pap (21 HGTa, 21 HGT1, 12 HGT2), and 29 low grade (LG) Pap (28 LGTa, 1 LGT1) tumors. 85 patients (63.4%) were BCG-naive. PIP data from 117 (87.3%) specimens, including 43 of 51 (84.3%) CIS specimens passed all QC measures and were included in analyses. PCA distinguished CIS from pure Pap specimens. Compared to HG Pap, CIS +/- conPap specimens demonstrated increased expression of EMT pathway genes including SNAI1/2, ZEB1, CDH1, GATA3, TWIST2, EPCAM (p Conclusions Comprehensive transcriptome profiling of archived CIS specimens is highly feasible including pure CIS samples. CIS tumors and tumors from durable responders to BCG therapy are characterized by unique gene expression signatures. Validation of these findings in prospective clinical trials is ongoing.