Prognostic Significance of Immune Cell Infiltration in Muscle-invasive Bladder Cancer Treated with Definitive Chemoradiation: A Secondary Analysis of RTOG 0524 and RTOG 0712

Chemoradiation therapy (CRT) is a treatment for muscle-invasive bladder cancer (MIBC). Using a novel transcriptomic profiling panel, we validated prognostic immune biomarkers to CRT using 70 pretreatment tumor samples from prospective trials of MIBC (NRG/RTOG 0524 and 0712). Disease-free survival (DFS) and overall survival (OS) were estimated via the Kaplan-Meier method and stratified by genes correlated with immune cell activation. Cox proportional-hazards models were used to assess group differences. Clustering of gene expression profiles revealed that the cluster with high immune cell content was associated with longer DFS (hazard ratio [HR] 0.53, 95% confidence interval [CI] 0.26-1.10; p = 0.071) and OS (HR 0.48, 95% CI 0.24-0.97; p = 0.040) than the cluster with low immune cell content. Higher expression of T-cell infiltration genes (CD8A and ICOS) was associated with longer DFS (HR 0.40, 95% CI 0.21-0.75; p = 0.005) and OS (HR 0.49, 95% CI 0.25-0.94; p = 0.033). Higher IDO1 expression (IFNγ signature) was also associated with longer DFS (HR 0.44, 95% CI 0.24-0.88; p = 0.021) and OS (HR 0.49, 95% CI 0.24-0.99; p = 0.048). These findings should be validated in prospective CRT trials that include biomarkers, particularly for trials incorporating immunotherapy for MIBC. PATIENT SUMMARY: We analyzed patient samples from two clinical trials (NRG/RTOG 0524 and 0712) of chemoradiation for muscle-invasive bladder cancer using a novel method to assess immune cells in the tumor microenvironment. Higher expression of genes associated with immune activation and high overall immune-cell content were associated with better disease-free survival and overall survival for patients treated with chemoradiation.

Racial Differences in the Detection Rate of Bladder Cancer Using Blue Light Cystoscopy: Insights from a Multicenter Registry

The use of blue light cystoscopy (BLC) has been shown to improve bladder tumor detection. However, data demonstrating the efficacy of BLC across different races are limited. Herein, we aim to evaluate heterogeneity in the characteristics of BLC for the detection of malignant lesions among various races. Clinicopathologic information was collected from patients enrolled in the multi-institutional Cysview® registry (2014-2021) who underwent transurethral resection or biopsy of bladder tumors. Outcome variables included sensitivity and negative and positive predictive values of BLC and white light cystoscopy (WLC) for the detection of malignant lesions among various races. Overall, 2379 separate lesions/tumors were identified from 1292 patients, of whom 1095 (85%) were Caucasian, 96 (7%) were African American, 51 (4%) were Asian, and 50 (4%) were Hispanic. The sensitivity of BLC was higher than that of WLC in the total cohort, as well as in the Caucasian and Asian subgroups. The addition of BLC to WLC increased the detection rate by 10% for any malignant lesion in the total cohort, with the greatest increase in Asian patients (18%). Additionally, the positive predictive value of BLC was highest in Asian patients (94%), while Hispanic patients had the highest negative predictive value (86%). Our study showed that regardless of race, BLC increases the detection of bladder cancer when combined with WLC.

Tumour tissue-derived small extracellular vesicles reflect molecular subtypes of bladder cancer

mRNA-based molecular subtypes have implications for bladder cancer prognosis and clinical benefit from certain therapies. Whether small extracellular vesicles (sEVs) can reflect bladder cancer molecular subtypes is unknown. We performed whole transcriptome RNA sequencing for formalin fixed paraffin embedded (FFPE) tumour tissues and sEVs separated from matched tissue explants, urine and plasma in patients with bladder cancer. sEVs were separated using size-exclusion chromatography, and characterized by transmission electron microscopy, nano flow cytometry and western blots, respectively. High yield of sEVs were obtained using approximately 1 g of tissue, incubated with media for 30 min. FFPE tumour tissue and tumour tissue-derived sEVs demonstrated good concordance in molecular subtype classification. All urinary sEVs were classified as luminal subtype, while all plasma sEVs were classified as Ba/Sq subtype, regardless of the molecular subtypes indicated by their matched FFPE tumour tissue. The comparison within urine sEVs, which may exclude the sample type specific background, could pick up the different biology between NMIBC and MIBC, as well as the signature genes related to molecular subtypes. Four candidate sEV-related bladder cancer-specific mRNA biomarkers, FAM71E2, OR4K5, FAM138F and KRTAP26-1, were identified by analysing matched urine sEVs, tumour tissue derived sEVs, and adjacent normal tissue derived sEVs. Compared to sEVs separated from biofluids, tissue-derived sEVs may reflect more tissue- or disease-specific biological features. Urine sEVs are promising biomarkers to be used for liquid biopsy-based molecular subtype classification, but the current algorithm needs to be modified/adjusted. Future work is needed to validate the four new bladder cancer-specific biomarkers in large cohorts.

Urinary IL-6 and IL-8 as predictive markers in bladder urothelial carcinoma: A pilot study

BACKGROUND

Cytokines are known to be a key a factor in numerous malignancies and to exert an important regulatory role in the tumor microenvironment. Interest has grown in understanding how cytokines modulate the tumor microenvironment and which cytokines may serve as markers of the tumor process; however, a complete picture of the cytokine landscape in bladder cancer remains unclear.

METHODS

Fresh urine specimens with sufficient volume were collected at random intervals. The urine concentrations of IL-8 (CXCL8), CCL18, and CXCL9 were determined using the standard commercially available enzyme immunoassay. The urine concentrations of IL-6 were determined using the high sensitivity enzyme immunoassay kit. Urinary cytokine concentrations were normalized with urinary creatinine concentrations.

RESULTS

Significantly elevated concentrations of IL-6 and IL-8 were detected in the urine from patients with urothelial carcinoma on follow-up compared to patients with benign follow-up. The presence of both IL-6 and IL-8 in the urine samples from the high grade urothelial carcinoma (HGUC) cohort revealed a clear discrimination when compared to samples from patients with benign follow-up. The presence of the combination of both IL-6 and IL-8 had a sensitivity of 90.0% and a specificity of 81.25%. Similar data were obtained when receiver operating characteristic analysis was performed on both IL-6 and IL-8 concentrations in the urine from patients with HGUC vs. the hematuria cohort.

CONCLUSIONS

The presence of IL-6 and IL-8 in urine specimens may have predictive value for urothelial carcinoma. However, a large longitudinal study is required to statistically eliminate confounding factors and support this theory.

Improved bladder cancer antitumor efficacy with a recombinant BCG that releases a STING agonist

Despite the introduction of several new agents for the treatment of bladder cancer (BC), intravesical BCG remains a first line agent for the management of non-muscle invasive bladder cancer. In this study we evaluated the antitumor efficacy in animal models of BC of a recombinant BCG known as BCG-disA-OE that releases the small molecule STING agonist c-di-AMP. We found that compared to wild-type BCG (BCG-WT), in both the orthotopic, carcinogen-induced rat MNU model and the heterotopic syngeneic mouse MB-49 model BCG-disA-OE afforded improved antitumor efficacy. A mouse safety evaluation further revealed that BCG-disA-OE proliferated to lesser degree than BCG-WT in BALB/c mice and displayed reduced lethality in SCID mice. To probe the mechanisms that may underlie these effects, we found that BCG-disA-OE was more potent than BCG-WT in eliciting IFN-β release by exposed macrophages, in reprogramming myeloid cell subsets towards an M1-like proinflammatory phenotypes, inducing epigenetic activation marks in proinflammatory cytokine promoters, and in shifting monocyte metabolomic profiles towards glycolysis. Many of the parameters elevated in cells exposed to BCG-disA-OE are associated with BCG-mediated trained innate immunity suggesting that STING agonist overexpression may enhance trained immunity. These results indicate that modifying BCG to release high levels of proinflammatory PAMP molecules such as the STING agonist c-di-AMP can enhance antitumor efficacy in bladder cancer.

Clinicopathologic and Survival After Cystectomy Outcomes in Squamous Cell Carcinoma of the Bladder

BACKGROUND

Squamous cell carcinoma of the bladder (SqCC) is a rare disease with limited management data. Thus, we sought to characterize the clinicopathologic and survival outcomes amongst patients with SqCC and explore the association of squamous differentiation within urothelial carcinoma (UC w/Squam), as compared to muscle invasive pure UC.

METHODS

We conducted a single-center retrospective cohort study of patients, stratified by histology, who underwent cystectomy for MIBC. Baseline clinicopathologic characteristics were compared, and overall survival was assessed using Kaplan-Meier method.

RESULTS

We identified 1,034 patients; 37 (3.58%) with SqCC histology, 908 (87.81%) with UC histology, and 89 (8.61%) with UC w/ Squam histology. Among SqCC patients, a higher proportion were Black and similarly a higher proportion were women; amongst patients with UC w/ Squam a higher proportion had lower BMI; and amongst patients with UC a higher proportion had lower clinical (c) T, cN, pathological (p) T, and pN stages. Patients presenting with UC were more likely to receive intravesical therapy; patients presenting with SqCC were less likely to receive neoadjuvant chemotherapy (NAC). Adjuvant chemotherapy rates were similar. With post-hoc Bonferroni analysis, overall survival, cancer-specific survival, and recurrence-free survival were significantly worse for the UC w/ Squam cohort.

CONCLUSIONS

UC w/ Squam histology was associated with worse survival outcomes after cystectomy for muscle invasive bladder cancer compared to UC. Our results suggest that UC w/ Squam is associated with more advanced disease compared to UC, warranting further prospective work on consideration of combination therapies for patients with this disease state.

Background and Update for ECOG-ACRIN EA8212: A Randomized Phase 3 Trial of Intravesical Bacillus Calmette-Guérin (BCG) Versus Intravesical Docetaxel and Gemcitabine Treatment in BCG-naïve High-grade Non-muscle-invasive Bladder Cancer (BRIDGE)

EA8212 BRIDGE is a phase 3 randomized trial comparing BCG vs GemDoce for BCG naïve high-risk non-muscle-invasive bladder cancer. This article provides an explanation for the rationale of the clinical trial and details the study design.

Identification of Lineage-specific Transcriptional Factor-defined Molecular Subtypes in Small Cell Bladder Cancer

Small cell/neuroendocrine bladder cancers (SCBCs) are rare and highly aggressive tumors that are associated with poor clinical outcomes. We discovered that lineage-specific transcription factors (ASCL1, NEUROD1, and POU2F3) defined three SCBC molecular subtypes that resemble well-characterized subtypes in small cell lung cancer. The subtypes expressed various levels of neuroendocrine (NE) markers and distinct downstream transcriptional targets. Specifically, the ASCL1 and NEUROD1 subtypes had high NE marker expression and were enriched with different downstream regulators of the NE phenotype (FOXA2 and HES6, respectively). ASCL1 was also associated with the expression of delta-like ligands that control oncogenic Notch signaling. POU2F3, a master regulator of the NE low subtype, targeted TRPM5, SOX9, and CHAT. We also observed an inverse association between NE marker expression and immune signatures associated with sensitivity to immune checkpoint blockade, and the ASCL1 subtype had distinct targets for clinically available antibody-drug conjugates. These findings provide new insight into molecular heterogeneity in SCBCs with implications for the development of new treatment regimens. PATIENT SUMMARY: We investigated the levels of different proteins in a specific type of bladder cancer (small cell/neuroendocrine; SCBC). We could identify three distinct subtypes of SCBC with similarity to small cell/neuroendocrine cancers in other tissues. The results may help in identifying new treatment approaches for this type of bladder cancer.

Exploring the potential of the novel imidazole-4,5-dicarboxyamide chemical exchange saturation transfer scaffold for pH and perfusion imaging

Here, we describe and assess the potential of 14 newly synthesized imidazole-4,5-dicarboxyamides (I45DCs) for pH and perfusion imaging. A number of these aromatic compounds possess large labile proton chemical shifts (up to 7.7 ppm from water) because of their intramolecular hydrogen bonds and a second labile proton to allow for chemical exchange saturation transfer (CEST) signal ratio-based pH measurements. We have found that the contrast produced is strong for a wide range of substitutions and that the inflection points in the CEST signal ratio versus pH plots used to generate concentration-independent pH maps can be adjusted based on these subsitutions to tune the pH range that can be measured. These I45DC CEST agents have advantages over the triiodobenzenes currently employed for tumor and kidney pH mapping, both preclinically and in initial human studies. Finally, as CEST MRI combined with exogenous contrast has the potential to detect functional changes in the kidneys, we evaluated our highest performing anionic compound (I45DC-diGlu) on a unilateral urinary obstruction mouse model and observed lower contrast uptake in the obstructed kidney compared with the unobstructed kidney and that the unobstructed kidney displayed a pH of ~ 6.5 while the obstructed kidney had elevated pH and an increased range in pH values. Based on this, we conclude that the I45DCs have excellent imaging properties and hold promise for a variety of medical imaging applications, particularly renal imaging.

Abdominal Mass in a Phenotypic Female with 46,XY Differences in Sex Development

We present a case of a large intra-abdominal mass found to be localized pure seminoma within a retained gonad of a 53-year-old phenotypic female with 46,XY differences in sex development (DSD) and androgen insensitivity syndrome (AIS). Our management included extirpation of the mass with contralateral gonadectomy. Historically, patients with AIS would undergo gonadectomy to mitigate the lifetime risk of testicular germ cell tumor development; however, growing evidence suggests safety in retention and surveillance of these gonads into adulthood. This case highlights the importance of lifetime surveillance of patients with 46,XY DSD who elect to retain their gonads.

Comparison of clinicopathological characteristics, gene expression profiles, mutational analysis, and clinical outcomes of pure and mixed small-cell carcinoma of the bladder

AIMS

Small cell bladder carcinoma (SCBC) is a rare, divergent form of urothelial carcinoma (UC). We aimed to determine whether pure (n = 16) and mixed (SCBC and UC; n = 30) tumours differed in pathology, gene expression characteristics, genetic alterations, and clinical outcomes.

METHODS AND RESULTS

Forty (87%) patients received first-line chemotherapy. Twenty-nine patients had no metastatic disease at diagnosis and underwent radical cystectomy. There were no differences in age, sex, race distribution, tumour size, stage at presentation, therapy response with pathological downstaging to ≤ypT1N0, or overall or progression-free survival (PFS) between pure and mixed tumours. There was a longer PFS among downstaged chemotherapy-responding tumours ≤ypT2N0M0 than among unresponsive tumours ≥ypT2 ≥ yN1M1 (P = 0.001). Patients who achieved pathological downstaging with neoadjuvant chemotherapy (n = 10) were stage cT2N0M0 at the time of diagnosis and were alive at the last follow-up (median 37 months), while 46% of patients who failed to achieve pathological downstaging were alive at the last follow-up (median 38 months; P = 0.008). RNA sequencing showed that the UC of mixed SCBC had similar neural expression signatures to pure SCBC. DNA sequencing revealed alterations in TERT (83%), P53 (56%), ARID1A (28%), RB1 (22%), and BRCA2 (11%). Immunohistochemistry for RB1 showed loss of expression in 18/19 (95%) patients, suggesting frequent pathway downregulation despite a low prevalence of RB1 mutation.

CONCLUSION

Patients with pure and mixed SCBC have similar outcomes and these outcomes are determined by the pathological stage at RC and are best among patients who have pathological downstaging after NAC.

Is a restaging TURBT necessary in high-risk NMIBC if the initial TURBT was performed with blue light?

OBJECTIVES

To evaluate whether a restaging transurethral resection of bladder tumor (TURBT) is necessary in high-risk nonmuscle invasive bladder cancer (NMIBC) if the initial TURBT was performed using blue light (BL) technology.

METHODS AND MATERIALS

Using the multi-institutional Cysview registry between 2014 and 2021, all consecutive adult patients with known NMIBC (Ta and T1 disease) who underwent TURBT followed by a restaging TURBT within 8 weeks were reviewed. Patients were stratified according to their initial TURBT, BL vs. white light (WL), and compared to determine rates of residual disease and upstaging. Univariate analysis was performed using Mann-Whitney U and chi-square tests, with P < 0.05 considered significant.

RESULTS

Overall, 115 patients had TURBT for NMIBC followed by a restaging TURBT within 8 weeks and were included in the analysis. Patients who underwent BL compared to WL for their initial TURBT had higher rates of benign pathology on restaging TURBT, although this was not statistically significant (47% vs. 30%; P = 0.08). Of patients with residual tumors on restaging TURBT, there were no differences in rates of Ta (22% vs. 26.5%; P = 0.62), T1 (22% vs. 26.5%; P = 0.62), or CIS (5.5% vs. 13%; P = 0.49) when the initial TURBT was done using BL compared to WL. Rates of upstaging to muscle invasive disease were also not different when initial TURBT was performed using BL compared to WL (3% vs. 4%; P = 0.78).

CONCLUSIONS

TURBT using BL does not reduce rates of residual disease or risk of upstaging on restaging TURBT in Ta or T1 disease. Thus, a restaging TURBT is still necessary even if initial TURBT was performed using BL.

Prostate multi-parametric magnetic resonance imaging appearance of diffuse adenosis of the peripheral zone (DAPZ)

Imaging specialists must recognize potential mimics of prostate cancer (PCa) on multi-parametric magnetic resonance imaging (mpMRI). We describe the appearance of diffuse adenosis of the peripheral zone (DAPZ) on mpMRI. The features of DAPZ parallel those of diffuse PCa, with low signal on T2-weighted images, rapid enhancement on dynamic contrast-enhanced sequences, and restricted diffusion. DAPZ is typically encountered in younger men with elevated prostate specific antigen (PSA) levels and portends an increased risk of the development of PCa. Recognition of the imaging appearance of DAPZ may reassure patients with concordant pathologic findings and may aid in selecting patients for follow-up.

Noninvasive assessment of renal dynamics and pH in a unilateral ureter obstruction model using DCE MR‐CEST urography

PURPOSE

To assess the potential of DCE MR CEST urography for assessing renal function in mice with unilateral ureter obstruction (UUO) by simultaneous pH and renal uptake/clearance measurements following injection of iopamidol.

METHODS

The right ureter of nine mice was obstructed via suture ligation. The animals were imaged at day 1, 2, and 3 post-obstruction on an 11.7T MRI scanner. Ninety-six sets of saturated CEST images at 4.3 and 5.5 ppm were collected. Renal pH values were obtained by calculating the signal ratio for these two frequencies and using a pH calibration curve. Renal time activity curves were measured as a percentage change in the post-injection CEST signal at 4.3 ppm relative to the average pre-injection signal.

RESULTS

For the healthy mice, the time activity curves of both kidneys were nearly identical and displayed rapid excretion of contrast. For the UUO mice, the dynamic CEST curves for the obstructed kidneys displayed prolonged time to peak (TTP) values and delayed contrast excretion compared with the contralateral (CL) kidneys. Renal pH maps of the healthy animals showed similar acidic values for both kidneys (pH 6.65 ± 0.04 vs 6.67 ± 0.02), whereas in the obstructed kidneys there was a significant increase in pH values compared with the CL kidneys (pH 6.67 ± 0.08 vs 6.79 ± 0.11 in CL and UUO kidneys, respectively).

CONCLUSION

Our findings indicate that DCE-MR-CEST urography can detect changes in renal uptake/excretion and pH homeostasis and distinguish between obstructed and unobstructed kidney as early as 1 day after UUO.

Abstract 3511: Varying Treatment outcomes of small molecule STING Agonist ADU-S100 in intratumoral and intravesical treatment regimens in syngeneic murine MB49 and in the N-methyl-N-nitrosourea (MNU) rat Model of urothelial carcinoma

Introduction: Intratumoral (IT) delivery of STING agonist ADU-S100 shows strong CD8+T cells-mediated antitumor immunity. However, rapid absorption from IT sites, short terminal half-life and adverse outcomes caused withdrawal of ADU-S100 from clinical trials. We reported development of BCG-STING, a preclinical candidate for non-muscle invasive bladder cancer (NMIBC) that overexpresses a bioactive STING agonist (c-di-AMP) and shows enhanced antitumor efficacy over BCG-WT by increasing tumor infiltrating CD4+ and CD8+ T cells and inflammatory macrophages. The similar mechanism of action prompted us to compare antitumor efficacy of BCG-STING with ADU-S100 in an IT as well as intravesical (IV) dosing regimen.

Methods: Syngeneic MB49 flank tumors in C57BL/6 female mice received IT treatment of BCG-WT, BCG-STING (5 x 106CFU) or ADU-S100 (100, 50 or 25 mg). Endpoint involved tumor volume measurement and flow-cytometry based tumor immune infiltrate analyses (at 100 μg). MNU carcinogen rat model of NMIBC and the standard IV administration regimen was used for BCG-WT or BCG-STING (5 x 106 CFU, 6x weekly) or ADU-S100 (25 μg, 6x weekly). Tumor involvement index (TII) and pathological tumor staging tumor involvement index were determined using histopathological analyses of MNU rat bladders.

Results: IT administration of ADU-S100 in MB49 tumor remained most-effective immunotherapy as compared to BCG-WT or BCG-STING even at lowest dose (25 μg), consistent with strongest infiltration of TNF-α+MHCII+F4/80+CD11b+ macrophages and IFN-γ+CD8+ T cells as compared to BCG-STING or BCG-WT. Strikingly, we observe a significant increase in immunosuppressive IL-10+ and ARG-1+ Ly6C(hi)Ly6G(-) monocytic myeloid-derived suppressor cells (M-MDSCs) in MB49 tumors treated with ADU-S100 and BCG-WT, but not BCG-STING. In contrast to MB49 model, IV induction course of BCG-STING in MNU rat model showed the greatest antitumor effects with only 5% residual TII compared to 30% in ADU-S100 or 42% in BCG-WT. Tumor staging displayed residual T1 (50%), CIS (25%) and Ta (25%) tumors in ADU-S100 group, while BCG-WT treated group showed a lower degree of invasion to the lamina propria with CIS (50%), T1 (25%) and Ta (25%) residual tumors. BCG-STING IV therapy resulted in 60% of rat bladders showing complete tumor regression while 40% had minimal residual non-invasive tumors.

Conclusions: The varying therapeutic outcomes of IT vs IV treatment regimens of ADU-S100 over BCG-STING or BCG-WT in different urothelial carcinoma models suggest the important role of varying tumor microenvironment and dosing regimens on relative antitumor efficacy. Increased percentage of immunosuppressive M-MDSCs specifically in response to ADU-S100 or BCG-WT suggests unique advantages associated with BCG-STING.

Citation Format: Alok K. Singh, Kara Lombardo, Monali Praharaj, James Liu, Russel Becker, Kelly Harris, Max Kates, David McConkey, Andres Matoso, William R. Bishai, Trinity Jude Bivalacqua. Varying Treatment outcomes of small molecule STING Agonist ADU-S100 in intratumoral and intravesical treatment regimens in syngeneic murine MB49 and in the N-methyl-N-nitrosourea (MNU) rat Model of urothelial carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3511.

BCG invokes superior STING-mediated innate immune response over radiotherapy in a carcinogen murine model of urothelial cancer

Radiation and bacillus Calmette-Guérin (BCG) instillations are used clinically for treatment of urothelial carcinoma, but the precise mechanisms by which they activate an immune response remain elusive. The role of the cGAS-STING pathway has been implicated in both BCG and radiation-induced immune response; however, comparison of STING pathway molecules and the immune landscape following treatment in urothelial carcinoma has not been performed. We therefore comprehensively analyzed the local immune response in the bladder tumor microenvironment following radiotherapy and BCG instillations in a well-established spontaneous murine model of urothelial carcinoma to provide insight into activation of STING-mediated immune response. Mice were exposed to the oral carcinogen, BBN, for 12 weeks prior to treatment with a single 15 Gy dose of radiation or three intravesical instillations of BCG (1 × 108  CFU). At sacrifice, tumors were staged by a urologic pathologist and effects of therapy on the immune microenvironment were measured using the NanoString Myeloid Innate Immunity Panel and immunohistochemistry. Clinical relevance was established by measuring immune biomarker expression of cGAS and STING on a human tissue microarray consisting of BCG-treated non-muscle-invasive urothelial carcinomas. BCG instillations in the murine model elevated STING and downstream STING-induced interferon and pro-inflammatory molecules, intratumoral M1 macrophage and T-cell accumulation, and complete tumor eradication. In contrast, radiotherapy caused no changes in STING pathway or innate immune gene expression; rather, it induced M2 macrophage accumulation and elevated FoxP3 expression characteristic of immunosuppression. In human non-muscle-invasive bladder cancer, STING protein expression was elevated at baseline in patients who responded to BCG therapy and increased further after BCG therapy. Overall, these results show that STING pathway activation plays a key role in effective BCG-induced immune response and strongly indicate that the effects of BCG on the bladder cancer immune microenvironment are more beneficial than those induced by radiation. © 2021 The Pathological Society of Great Britain and Ireland.

Intravesical sequential gemcitabine and docetaxel versus bacillus calmette-guerin (BCG) plus interferon in patients with recurrent non-muscle invasive bladder cancer following a single induction course of BCG

INTRODUCTION

Repeat BCG induction remains an option for select non-muscle invasive bladder cancer (NMIBC) patients who fail initial therapy. Alternative salvage intravesical regimens such as Gemcitabine and Docetaxel (Gem/Doce) have been investigated. We aimed to compare the efficacy BCG plus interferon a-2b (BCG/IFN) and Gem/Doce in patients with recurrent NMIBC after a single prior BCG course.

METHODS

The National Phase II BCG/IFN trial database and multi-institutional Gem/Doce database were queried for patients with recurrent NMIBC after one prior BCG induction course, excluding those with BCG unresponsive disease. Stabilized inverse probability treatment weighted survival curves were estimated using the Kaplan-Meier method and compared. Propensity scores were derived from a logistic regression model. The primary outcome was recurrence free survival (RFS); secondary outcomes were high-grade (HG) RFS and risk factors for treatment failure.

RESULTS

We identified 197 BCG/IFN and 93 Gem/Doce patients who met study criteria. Patients receiving Gem/Doce were older and more likely to have HG disease, CIS, and persistent disease following induction BCG (all P < 0.01). After propensity score-based weighting, the adjusted 1- and 2-year RFS was 61% and 53% after BCG/IFN versus 68% and 46% after Gem/Doce (P = 0.95). Adjusted 1- and 2-year HG-RFS was 60% and 51% after BCG/IFN versus 63% and 42% after Gem/Doce (P = 0.68). Multivariable Cox regression revealed that Gem/Doce treatment was not associated with an increased risk of failure (HR = 0.97, P = 0.89) as compared to BCG/IFN.

CONCLUSION

Patients with recurrent NMIBC after a single induction BCG failure and not deemed BCG unresponsive had similar oncologic outcomes with Gem/Doce and BCG/IFN in a post-hoc analysis. Additional prospective studies are needed.

Race, ethnicity, and gender reporting in North American clinical trials for BCG-unresponsive non-muscle invasive bladder cancer

INTRODUCTION

The National Institutes of Health (NIH) Revitalization Act of 1993 established guidelines for the inclusion of racial/ethnic minorities and women in clinical research. However, the reporting rate of such patient demographic data in clinical trials for BCG-unresponsive non-muscle invasive bladder cancer is not well characterized.

METHODS

We identified published clinical trials of all phases (I -III) for BCG-unresponsive non-muscle invasive bladder cancer conducted in the US and/or Canada. We calculated the proportion of studies reporting patient gender and race/ethnicity, tabulating these data when present. We compared reported trial participant race, ethnicity and gender with the number of new bladder cancer cases and deaths using the Centers for Disease Control and Prevention (CDC) and National Cancer Institute (NCI) U.S. Cancer Statistics data from 2013 -2017.

RESULTS

We identified 27 trials published from 1998 -2021 enrolling a total of 1673 patients. While all trials included data on patient gender (22% women overall), only 40.7% included any data on patient race/ethnicity. Among those that did, trial participants were reported as white (94%), Black (2.1%), Hispanic (0.6%), Asian (0.9%), and Other (2.3%). Racial/ethnic minorities were underrepresented in clinical trials relative to their proportion of new bladder cancer cases and deaths.

CONCLUSION

Most clinical trials that have been conducted for BCG-unresponsive non-muscle invasive bladder cancer do not report data on patient race or ethnicity despite NIH guidelines advocating for inclusion of such data. Racial/ethnic minorities remain underrepresented in these trials relative to the burden of bladder cancer prevalence and mortality faced by these groups.

Indeterminate atypia in urinary tract cytology: Does it really matter?

The study of atypia in urinary cytology has been ongoing for decades but most studies have focused primarily on test performance in patients with concurrent biopsies and/or limited follow-up periods. While these data are useful, many studies fail to consider patient factors that may alter the pretest probability, which can subsequently affect test performance. An isolated diagnosis of malignancy in urinary cytology usually has a high positive predictive value and allows a urologist to conduct a rigorous workup of the patient to establish a tissue diagnosis. However, it is less certain how an atypical diagnosis impacts patient care, given that many patients have a history of bladder cancer and are already under surveillance with cystoscopy at regular screening intervals. Furthermore, a discrete negative urine cytology is unlikely to allow a patient to forego a cystoscopy procedure due to limitations in the sensitivity of urine cytology. Over the last several years, the introduction of The Paris System for Reporting Urinary Cytology (TPS) has improved the predictive value of atypical diagnoses, but additional studies are needed to evaluate the performance of these diagnoses in specific clinical situations. Such data could better inform urologists on how to manage patients with atypical diagnoses. This review discussed the diagnosis of atypia in urinary cytology and the impact of such a diagnosis in various clinical contexts.

Safety and Efficacy of Reproductive Organ-Sparing Radical Cystectomy in Women With Variant Histology and Advanced Stage

PURPOSE

Muscle invasive bladder cancer surgical management has been historically a radical cystoprostatectomy in males and an anterior exenteration in females. Uterine, ovarian, and vaginal preservation are utilized, but raise concerns regarding risk to oncologic control, especially in variant histopathology or advanced stage.

MATERIALS AND METHODS

A retrospective single institutional analysis identified radical cystectomies performed in women, including those with variant histology, which were defined as reproductive organ sparing (uterine, vaginal, and ovary sparing) or nonorgan sparing. The Kaplan-Meier method was used for recurrence-free survival (RFS), cancer-specific survival (CSS), and overall survival (OS) in patients with advanced disease.

RESULTS

From 2000 to 2020, 289 women were identified, 188 underwent reproductive organ-sparing cystectomy. No statistical differences were noted for clinical parameters or presence of variant histology for organ-sparing (ROS) and nonorgan-sparing (non-ROS). Positive margin rates did not differ for ROS and non-ROS; 4.3% vs. 7.9%, P = .19, respectively. Median RFS was not statistically significantly different for ROS vs. non-ROS (26.1 vs. 15.3 months) P = .937 hazard ratio (HR) 1.024. CSS was not statistically different for ROS vs. non-ROS (36.3 vs. 28.6 months), P = .755 HR 0.9. OS was not statistically different for ROS vs. non-ROS (25.8 vs. 23.8 months), P = .5 HR = 1.178. Variant histology did not change survival (HR 1.1, P = .643).

CONCLUSION

In this analysis, ROS in women with advanced disease did not increase positive margin rates or decrease RFS, CSS, or OS compared to non-ROS. Variant histology did not decrease survival odds. Based on preoperative assessment and intraoperative findings, ROS in patients with variant histology and advanced disease should be considered.

A Molecular Inquiry into the Role of Antibody-Drug Conjugates in Bacillus Calmette-Guérin-exposed Non-muscle-invasive Bladder Cancer

The treatment landscape for advanced urothelial cancer has changed dramatically owing to the US Food and Drug Administration approval and introduction of antibody-drug conjugates (ADCs), including enfortumab vedotin and sacituzumab govitecan. Efforts have begun to use these therapies in earlier disease states, specifically bacillus Calmette-Guérin (BCG)-unresponsive non-muscle-invasive bladder cancer (NMIBC). We assessed gene expression associated with these newly approved therapies in a novel cohort of treatment-naïve NMIBC tumors before and after BCG therapy. Multiple genes, including Nectin-4, Trop-2, and Her-2, exhibited increased expression after BCG therapy compared to baseline. However, few of the tumors with increased expression of ADC targets also exhibited increased PD-L1/PD-1 expression. Taken together, these data demonstrate the heterogeneous genomic landscape of BCG-exposed NMIBC, and provide evidence supporting the evaluation of ADCs in NMIBC. PATIENT SUMMARY: We evaluated the potential role of targeted therapies that have been approved in the USA for advanced non-muscle-invasive bladder cancer (NMIBC) that has recurred after treatment with bacillus Calmette-Guérin (BCG). By assessing levels of specific genes and proteins linked to the targeted therapies, we demonstrate that there is rationale for further evaluation of these therapies in NMIBC.

Role of blue-light cystoscopy in detecting invasive bladder tumours: data from a multi-institutional registry

OBJECTIVES

To evaluate the role of blue-light cystoscopy (BLC) in detecting invasive tumours that were not visible on white-light cystoscopy (WLC).

PATIENTS AND METHODS

Using the multi-institutional Cysview registry database, patients who had at least one white-light negative (WL-)/blue-light positive (BL+) lesion with invasive pathology (≥T1) as highest stage tumour were identified. All WL-/BL+ lesions and all invasive tumours in the database were used as denominators. Relevant baseline and outcome data were collected.

RESULTS

Of the 3514 lesions (1257 unique patients), 818 (23.2%) lesions were WL-/BL+, of those, 55 (7%) lesions were invasive (48 T1, seven T2; 47 unique patients) including 28/55 (51%) de novo invasive lesions (26 unique patients). In all, 21/47 (45%) patients had WL-/BL+ concommitant carcinoma in situ and/or another T1 lesions. Of 22 patients with a WL-/BL+ lesion who underwent radical cystectomy (RC), high-risk pathological features leading to RC was only visible on BLC in 18 (82%) patients. At time of RC, 11/22 (50%) patients had pathological upstaging including four (18%) with node-positive disease.

CONCLUSIONS

A considerable proportion of invasive lesions are only detectable by BLC and the rate of pathological upstaging is significant. Our present findings suggest an additional benefit of BLC in the detection of invasive bladder tumours that has implications for treatment approach.

Preclinical evaluation of a hypotonic docetaxel nanosuspension formulation for intravesical treatment of non-muscle-invasive bladder cancer

Intravesical chemotherapy is a key approach for treating refractory non-muscle-invasive bladder cancer (NMIBC). However, the effectiveness of intravesical chemotherapy is limited by bladder tissue penetration and retention. Here, we describe the development of a docetaxel nanosuspension that, when paired with a low osmolality (hypotonic) vehicle, demonstrates increased uptake by the bladder urothelium with minimal systemic exposure. We compare the bladder residence time and efficacy in an immune-competent rat model of NMIBC to the clinical comparator, solubilized docetaxel (generic Taxotere) diluted for intravesical administration. We found that only the intravesical docetaxel nanosuspension significantly decreased cell proliferation compared to untreated tumor tissues. The results presented here suggest that the combination of nanoparticle-based chemotherapy and a hypotonic vehicle can provide more efficacious local drug delivery to bladder tissue for improved treatment of refractory NMIBC.

Predictive models of response to neoadjuvant chemotherapy in muscle-invasive bladder cancer using nuclear morphology and tissue architecture

Characterizing likelihood of response to neoadjuvant chemotherapy (NAC) in muscle-invasive bladder cancer (MIBC) is an important yet unmet challenge. In this study, a machine-learning framework is developed using imaging of biopsy pathology specimens to generate models of likelihood of NAC response. Developed using cross-validation (evaluable N = 66) and an independent validation cohort (evaluable N = 56), our models achieve promising results (65%-73% accuracy). Interestingly, one model-using features derived from hematoxylin and eosin (H&E)-stained tissues in conjunction with clinico-demographic features-is able to stratify the cohort into likely responders in cross-validation and the validation cohort (response rate of 65% for predicted responder compared with the 41% baseline response rate in the validation cohort). The results suggest that computational approaches applied to routine pathology specimens of MIBC can capture differences between responders and non-responders to NAC and should therefore be considered in the future design of precision oncology for MIBC.

Expression of Nectin-4 in Bladder Urothelial Carcinoma, in Morphologic Variants, and Nonurothelial Histotypes

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.

Four versus 3 Cycles of Neoadjuvant Chemotherapy for Muscle-Invasive Bladder Cancer: Implications for Pathological Response and Survival

PURPOSE

The ideal number of neoadjuvant chemotherapy (NAC) cycles for muscle-invasive bladder cancer is uncertain with 3 to 4 representing the standard of care (SOC). We compared ypT0 rates and survival between patients receiving 4 versus 3 cycles of NAC with evaluation of chemotherapy-related toxicity for correlation with tumor chemosensitivity and pathological response.

MATERIALS AND METHODS

Patients receiving NAC followed by radical cystectomy for cT2-4N0M0 urothelial carcinoma from 2 institutions were included. Primary study groups included 4 cisplatin-based NAC cycles, 3 cisplatin-based NAC cycles, and nonSOC NAC (1-2 cycles or noncisplatin-based) to compare ypT0/≤ypT1 rates and survival. A cohort of patients not receiving NAC was included for pathological reference.

RESULTS

Of 693 total patients, 318 (45.9%) received NAC. ypT0 and ≤ypT1 rates were 42/157 (26.8%) and 86/157 (54.8%) for 4 cycles, 38/114 (33.3%) and 71/114 (62.3%) for 3 cycles, and 6/47 (12.8%) and 13/47 (27.7%) for nonSOC (p=0.03 and p <0.01, respectively). Pathological response appeared higher among patients receiving 3 cycles due to toxicity (ypT0: 29/77 [37.7%]; ≤ypT1: 51/77 [66.2%]) but did not reach statistical significance. Toxicities leading to treatment modifications were thrombocytopenia (32.1%), neutropenia (27.2%), renal insufficiency (22.2%), and constitutional symptoms (18.5%). NonSOC patients had lower Kaplan-Meier survival (cT2-cT4N0M0: log-rank p=0.07; cT2N0M0: log-rank p=0.02). There were no statistically significant differences in survival between 4 and 3 cycles (HR 1.00 [95% CI 0.57-1.74], p=0.99).

CONCLUSIONS

Patients completing 3 cycles of cisplatin-based NAC have similar pathologic response and short-term survival compared to 4 cycles. Further evaluation of patients experiencing toxicity as a potential marker of tumor chemosensitivity is needed.

Dynamic Contrast Enhanced-MR CEST Urography: An Emerging Tool in the Diagnosis and Management of Upper Urinary Tract Obstruction

Upper urinary tract obstructions (UTOs) are blockages that inhibit the flow of urine through its normal course, leading to impaired kidney function. Imaging plays a significant role in the initial diagnosis of UTO, with anatomic imaging (primarily ultrasound (US) and non-contrast computed tomography (CT)) serving as screening tools for the detection of the dilation of the urinary collecting systems (i.e., hydronephrosis). Whether hydronephrosis represents UTO or a non-obstructive process is determined by functional imaging (typically nuclear medicine renal scintigraphy). If these exams reveal evidence of UTO but no discernable source, multiphase contrast enhanced CT urography and/or dynamic contrast enhanced MR urography (DCE-MRU) may be performed to delineate a cause. These are often performed in conjunction with direct ureteroscopic evaluation. While contrast-enhanced CT currently predominates, it can induce renal injury due to contrast induced nephropathy (CIN), subject patients to ionizing radiation and is limited in quantifying renal function (traditionally assessed by renal scintigraphy) and establishing the extent to which hydronephrosis is due to functional obstruction. Traditional MRI is similarly limited in its ability to quantify function. DCE-MRU presents concerns regarding nephrogenic systemic fibrosis (NSF), although decreased with newer gadolinium-based contrast agents, and regarding cumulative gadolinium deposition in the basal ganglia. DCE-MR CEST urography is a promising alternative, employing new MRI contrast agents and imaging schemes and allowing for concurrent assessment of renal anatomy and functional parameters. In this review we highlight clinical challenges in the diagnosis and management of UTO, identify key advances in imaging agents and techniques for DCE-MR CEST urography and provide perspective on how this technique may evolve in clinical importance.

Urothelial Carcinoma In Situ of the Bladder: Correlation of CK20 Expression With Adaptive Immune Resistance, Response to BCG Therapy, and Clinical Outcome

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.

Development and validation of a NanoString BASE47 bladder cancer gene classifier

Background

Recent molecular characterization of urothelial cancer (UC) has suggested potential pathways in which to direct treatment, leading to a host of targeted therapies in development for UC. In parallel, gene expression profiling has demonstrated that high-grade UC is a heterogeneous disease. Prognostic basal-like and luminal-like subtypes have been identified and an accurate transcriptome BASE47 classifier has been developed. However, these phenotypes cannot be broadly investigated due to the lack of a clinically viable diagnostic assay. We sought to develop and evaluate a diagnostic classifier of UC subtype with the goal of accurate classification from clinically available specimens.

Methods

Tumor samples from 52 patients with high-grade UC were profiled for BASE47 genes concurrently by RNAseq as well as NanoString. After design and technical validation of a BASE47 NanoString probeset, results from the RNAseq and NanoString were used to translate diagnostic criteria to the Nanostring platform. Evaluation of repeatability and accuracy was performed to derive a final Nanostring based classifier. Diagnostic classification resulting from the NanoString BASE47 classifier was validated on an independent dataset (n = 30). The training and validation datasets accurately classified 87% and 93% of samples, respectively.

Results

Here we have derived a NanoString-platform BASE47 classifier that accurately predicts basal-like and luminal-like subtypes in high grade urothelial cancer. We have further validated our new NanoString BASE47 classifier on an independent dataset and confirmed high accuracy when compared with our original Transcriptome BASE47 classifier.

Conclusions

The NanoString BASE47 classifier provides a faster turnaround time, a lower cost per sample to process, and maintains the accuracy of the original subtype classifier for better clinical implementation.

Evaluation of Incisional Negative Pressure Wound Therapy in the Prevention of Surgical Site Occurrences After Radical Cystectomy: A New Addition to Enhanced Recovery After Surgery Protocol

BACKGROUND

Surgical site infection (SSI) remains a significant complication after radical cystectomy (RC). Enhanced recovery after surgery (ERAS) focuses on interventions to decrease length of stay, but few address wound-related complications directly.

OBJECTIVE

To determine the impact that prophylactic incisional negative pressure wound therapy (iNPWT) will have to reduce the rate of surgical site occurrences (SSOs = SSI + seroma + superficial dehiscence) after RC.

DESIGN, SETTINGS, AND PARTICIPANTS

We retrospectively reviewed patients undergoing RC by a single surgeon from 2012 to 2017. As part of our ERAS pathway, we employed prophylactic iNPWT during abdominal closure and compared it with a contemporary cohort of standard wound closure.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

We compared 90-d SSIs, SSOs, and readmissions between iNPWT and standard skin staple closure. Univariate and multivariate regressions were used to compare the two groups.

RESULTS AND LIMITATIONS

We identified 158 (104 iNPWT, 54 standard) patients from 2012 to 2017. The rates of SSIs and SSOs were 9.7% and 19.0%, respectively. The overall readmission rate for the cohort was 21.5%, with 4.4% of patients requiring readmission for SSI. The iNPWT group had lower rates of SSIs (5.8% vs 16.7%, p = 0.03) and SSOs (11.5% vs 33.3%, p < 0.01). There was no difference between the groups for readmission (21.1% vs 22.2%, p = 0.5). The iNPWT protected against both SSI (odds ratio [OR] 0.89, 95% confidence interval [CI]: 0.81-0.98) and 90-d SSO (OR 0.77, 95% CI: 0.68-0.87).

CONCLUSIONS

Prophylactic iNPWT is feasible after RC with a modest decrease in both 90-d SSIs and 90-d SSOs, but not readmissions. Wound closure assisted by iNPWT should be considered in RC ERAS pathways.

PATIENT SUMMARY

In this report, we looked at the impact of new vacuum suction dressing on the prevention of surgical infections after radical cystectomy (RC). We found that this wound dressing can decrease the impact of surgical infections and aid in recovery after RC.

Multi-Institution Evaluation of Sequential Gemcitabine and Docetaxel as Rescue Therapy for Nonmuscle Invasive Bladder Cancer

PURPOSE

Rescue intravesical therapies for patients with bacillus Calmette-Guérin failure nonmuscle invasive bladder cancer remain a critical focus of ongoing research. Sequential intravesical gemcitabine and docetaxel therapy has shown safety and efficacy in 2 retrospective, single institution cohorts. This doublet has since been adopted as an intravesical salvage option at multiple institutions. We report the results of a multi-institutional evaluation of gemcitabine and docetaxel.

MATERIALS AND METHODS

Each institution retrospectively reviewed all records of patients treated with intravesical gemcitabine and docetaxel for nonmuscle invasive bladder cancer between June 2009 and May 2018. Only patients with recurrent nonmuscle invasive bladder cancer and a history of bacillus Calmette-Guérin treatment were included in the analysis. If patients were disease-free after induction, maintenance was instituted at the treating physician's discretion. Posttreatment surveillance followed American Urological Association guidelines. Survival analysis was performed using the Kaplan-Meier method and risk factors for treatment failure were assessed with Cox regression models.

RESULTS

Overall 276 patients (median age 73 years, median followup 22.9 months) received treatment. Nine patients were unable to tolerate a full induction course. One and 2-year recurrence-free survival rates were 60% and 46%, and high grade recurrence-free survival rates were 65% and 52%, respectively. Ten patients (3.6%) had disease progression on transurethral resection. Forty-three patients (15.6%) went on to cystectomy (median 11.3 months from induction), of whom 11 (4.0%) had progression to muscle invasion. Analysis identified no patient, disease or prior treatment related factors associated with gemcitabine and docetaxel failure.

CONCLUSIONS

Intravesical gemcitabine and docetaxel therapy is well tolerated and effective, providing a durable response in patients with recurrent nonmuscle invasive bladder cancer after bacillus Calmette-Guérin therapy. Further prospective study is warranted.

Feasibility of digital pathology of circulating tumor cells with morphologic analysis in localized bladder cancer

525

Background: Circulating tumor cells (CTCs) are promising biomarkers in metastatic urothelial cancer (UC). Unfortunately, efforts in localized disease have been unsuccessful, in part due to limitations of existing technologies that rely on counting cells and epithelial-marker expression. Here, we applied a novel selection-free digital pathology platform in a localized UC cohort. To date, this platform has associated CTC morphology with differential therapeutic response in metastatic UC and castrate-resistant prostate cancer. If feasible in localized UC, we may potentially identify best candidates for adjuvant therapy or bladder sparing, as well as enable sensitive monitoring for recurrence. Methods: N=16 consecutive UC pts included 8 (50%) metastatic controls and 8 (50%) localized (3 (37%) at TURBT and 5 (63%) at cystectomy). Peripheral blood was processed with the Epic CTC platform (pan-CK/CD45/PD-L1/DAPI staining). Approximately 3 million cells per slide were imaged. Unsupervised clustering categorized CTCs into 5 subtypes based on 11 morphologic features (nuclear solidity, speckling, nucleoli and entropy; cytokeratin speckling and ratio; and cytoplasmic/nuclear circularity, area, and convex area ratio). Results: 119 CTCs were detected from 11/16 (69%) pts (5/8 (63%) localized (2 NMIBC, 6 MIBC) and 6/8 (75%) metastatic). All MIBC pts had cystectomy (4/6 (67%) received NAC). 2/8 (25%) metastatic pts had stable disease, 3/8 (38%) were progressing, and 3/8 (38%) had newly detected M1. Median (range) CTC count/mL was similar for localized and metastatic pts (0.4 (0-58.6), 0.75 (0-1.9)). CTCs were detected in a pt with CIS, but not in a pt with TaHG disease. 1/16 (6.3%) pts had a single PD-L1+ CTC. CTCs were successfully assigned into 5 subtypes with predominant features of large, small, or linear cells, high cytoplasmic circularity, and prominent nucleoli. Conclusions: Digital pathology and subtype assignment of CTCs is feasible in localized UC. Ongoing efforts at our center include application of this technology in localized patients receiving investigational checkpoint inhibitor therapy to potentially predict best responders or conversely those at the highest risk for recurrence.

Impact of spheroid culture on molecular and functional characteristics of bladder cancer cell lines

The three-dimensional cell culture system is an increasingly important technique for discovering new biological aspects of cancer cells. In the present study it was demonstrated that bladder cancer cell lines, RT4 and 5637, spontaneously formed round multicellular spheroids (MCSs) in suspension by the aggregation method. MCSs consisted of cells differentially expressing luminal/basal markers. Western blotting showed that PPARγ and forkhead box A1 (FOXA1)of luminal markers were expressed to a lesser extent in MCSs than in parental cells grown in two-dimensional (2D) adherent culture. Cells in MCSs in suspension proliferated less efficiently, and were more resistant to cisplatin (CDDP) and gemcitabine than parental cells grown in 2D culture. Culturing cell lines as MCSs in suspension is a notable platform to decipher alternative biological aspects of bladder cancer cells, which could not be unraveled by the conventional 2D adherent culture.

Optimizing pharmacokinetics of intravesical chemotherapy for bladder cancer

Non-muscle-invasive bladder cancer (NMIBC) remains one of the most common malignancies and is associated with considerable treatment costs. Patients with intermediate-risk or high-risk disease can be treated with intravesical BCG, but many of these patients will experience tumour recurrence, despite adequate treatment. Standard of care in these patients is radical cystectomy with urinary diversion, but this approach is associated with considerable morbidity and lifestyle modification. As an alternative, perioperative intravesical chemotherapy is recommended for low-risk papillary NMIBC, and induction intravesical chemotherapy is an option for patients with intermediate-risk NMIBC and BCG-unresponsive NMIBC. However, poor pharmaceutical absorption and drug washout during normal voiding can limit sustained drug concentrations in the urothelium, which reduces efficacy, and small-molecule chemotherapeutic agents can be absorbed through the urothelium into the bloodstream, leading to systemic adverse effects. Several novel drug delivery methods - including hyperthermia, mechanical sustained released devices and nanoparticle drug conjugation - have been developed to overcome these limitations. These novel methods have the potential to be combined with established chemotherapeutic agents to change the paradigm of NMIBC treatment.

Abstract 3253: Next-gen STING-agonist like BCG confers enhanced immunogenicity and antitumor efficacy in vitro and in vivo

INTRODUCTION: Stimulator of interferon genes (STING), a cytosolic sensor of cyclic dinucleotide (CDN; c-di-AMP and c-di-GMP) activates type I interferons (IFN I) and pro-inflammatory cytokines. Recombinant Bacillus-Calmette Guerin (BCG) overexpressing CDN (STING-agonist) remains unexplored in non-muscle invasive bladder cancer (NMIBC). We hypothesize that intravesical recombinant BCG is more efficacious than BCG for NMIBC. We constructed a novel STING-agonist-like recombinant BCG Pasteur and Tice strains (rBCG-disA-OE) carrying plasmids that harbors di-adenylate cyclase (disA) gene to test this hypothesis.

METHODS: WT and rBCG-disA-OE were tested for immunotherapeutic potential in WT and STING-deficient murine macrophages, to ascertain STING-dependent IFN I and pro-inflammatory cytokines activation. Similar experiments were conducted in RT4, J5637, and NBT2 cell lines. Fisher 344 rats intravesically received 4 doses of 1.5 mg/kg N methyl N nitrosurea (MNU) to induce NMIBC. Intravesical instillation of WT- and rBCG-disA-OE was administered weekly x 6. Histologic tumor grade, tumor involvement index, gene expression (q-PCR) as well as systemic immune responses (ELISA) were assessed. Growth and virulence of rBCG-disA-OE in BALB/c and SCID mice were tested using aerosol infection protocol.

RESULTS: rBCG-disA-OE Pasteur and TICE strains overexpressing STING-agonist were potent inducers of IFN I in STING-dependent manner in murine macrophages. IFN I induction by rBCG-disA-OE increased TNF-α (P=0.01), IL-6 (P=0.04) and IL-1β (P=0.004) in bladder cancer cells and murine macrophages. Intravesical instillation of rBCG-disA-OE in MNU-rats resulted into significantly (P=0.004) lower tumor involvement index accompanied by a potent induction of IFN I signaling, M1 macrophage associated cytokines (Nos2, P=0.05 & IL-6 P=0.05) and chemokines (CCL2, P=0.048 & MCP-1, P=0.05). rBCG-disA-OE prevented invasive cancer when compared WT-BCG. BALB/c mice infected with rBCG-disA-OE showed significantly less lung bacillary burden (P=0.005) suggesting strain attenuation. SCID-mice infected with rBCG-disA-OE had prolonged survival.

CONCLUSION: We demonstrate STING-agonist like rBCG-disA-OE is superior to WT-BCG for induction of macrophage cytotoxicity and activation of IFN I signaling. rBCG-disA-OE demonstrated enhanced antitumor activity and cytokine production in a pre-clinical model of NMIBC suggesting an alternative intravesical agent in BCG unresponsive population.

Note: This abstract was not presented at the meeting.

Citation Format: Alok K. Singh, Monali Praharaj, Gregory A. Joice, Takahiro Yoshida, Max Kates, David McConkey, William R. Bishai, Trinity J. Bivalacqua. Next-gen STING-agonist like BCG confers enhanced immunogenicity and antitumor efficacy in vitro and in vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3253.