Current Clinical Trials in Non-muscle Invasive Bladder Cancer

Heterogeneity of BCG unresponsive bladder cancer clinical trials limits patients' access to novel therapeutics

INTRODUCTION

Effective therapies for patients with nonmuscle invasive bladder cancer that recurs or progresses after Bacille Calmette-Guérin (BCG) are lacking. This unmet need is the focus of many drug development efforts, reflected in many completed/ongoing/planned clinical trials for patients with BCG unresponsive bladder cancer. Though BCG unresponsive criteria are well defined, enrollment criteria are variable such that, even at centers with several open trials in this space, a given patient with BCG unresponsive bladder cancer might not qualify for any. To understand the scope of this dilemma, we systematically analyzed enrollment criteria for all BCG unresponsive protocols registered on ClinicalTrials.gov to quantify heterogeneity in enrollment criteria and to determine what proportion of trials were inclusive to patients meeting U.S. Food and Drug Administration (FDA) BCG unresponsive criteria.

METHODS

The ClinicalTrials.gov search tool was queried for relevant trials using the terms "bladder cancer" "nonmuscle invasive bladder cancer" and "BCG". Previously published review articles were cross-referenced to ensure that search results were comprehensive. Inclusion and exclusion criteria for the resulting 31 protocols pertaining to distinct categories such as performance status, laboratory parameters, co-morbidities, active medications, and prior therapies were recorded. Based on enrollment criteria, the trial was assessed as fully inclusive or not to patients considered to be BCG unresponsive by the 2018 FDA criteria.

RESULTS

Of 31 trials, 15 (48%) had inclusion/exclusion criteria that were fully consistent with (inclusive of patients that met) the BCG unresponsive bladder cancer definition. 18 (58%) of trials excluded patients with a history of prior pelvic radiation therapy. 14 (45%) of trials excluded patients with ECOG performance status >2 (or Karnofsky Performance Status equivalent). The most common disease specific exclusion for patients with BCG unresponsive bladder cancer was a requirement for stage Tis (carcinoma in situ, CIS), which pertained to 7 (23%) of trials.

CONCLUSIONS

Enrollment criteria for patients with BCG unresponsive bladder cancer are highly variable. Over half of trials evaluated do not meet stringent criteria for this disease state based upon treatment history and cancer staging requirements. For patients who desire to enroll in clinical trials, this restricts access to novel agents. For bladder cancer treating physicians and regulatory bodies, this also hinders comparisons across agents.

ALT-803 in the treatment of non-muscle-invasive bladder cancer: Preclinical and clinical evidence and translational potential

Bladder cancer (BCa) is one of the most common malignant tumors that cause death. Approximately 75%–85% of BCa develop into non-muscle-invasive bladder cancer (NMIBC). Bacillus Calmette-Guérin (BCG) is the gold standard for avoiding cystectomy in the treatment of NMIBC. Unfortunately, up to 30% of patients do not respond to BCG treatment, and up to 70% of BCG responders relapse. The United States Food and Drug Administration (FDA) approved valrubicin (1998) and pembrolizumab (2020) for the treatment of BCG-unresponsive (BCGu) NMBIC. However, the complete remission rate for valrubicin and pembrolizumab was only 16% and 40.6%, respectively. ALT-803 (N-803) is an IL-15 superagonist and reduces tumor burden by promoting the proliferation and activation of NK cells and CD8⁺ T cells. The FDA received (23 May 2022) and accepted to review (28 July 2022) the marketing submission of ALT-803 plus BCG for the treatment of BCGu NMIBC. However, the FDA previously rejected the application for oportuzumab monatox (OM) due to a lack of data comparing it with pembrolizumab on August 20, 2021. Interestingly, the clinical efficacy and safety of ALT-803 were higher than that of pembrolizumab and OM, suggesting that ALT-803 may be approved by FDA. This review aims to further knowledge of the preclinical and clinical evidence of ALT-803 in the treatment of NMIBC and discuss its translational potential.

Are We Ready to Implement Molecular Subtyping of Bladder Cancer in Clinical Practice? Part 1: General Issues and Marker Expression

Bladder cancer (BC) is a heterogeneous disease with highly variable clinical and pathological features, and resulting in different outcomes. Such heterogeneity ensues from distinct pathogenetic mechanisms and may consistently affect treatment responses in single patients. Thus, over the last few years, several groups have developed molecular classification schemes for BC, mainly based on their mRNA expression profiles. A “consensus” classification has recently been proposed to combine the published systems, agreeing on a six-cluster scheme with distinct prognostic and predictive features. In order to implement molecular subtyping as a risk-stratification tool in routine practice, immunohistochemistry (IHC) has been explored as a readily accessible, relatively inexpensive, standardized surrogate method, achieving promising results in different clinical settings. The first part of this review deals with the steps resulting in the development of a molecular subtyping of BC, its prognostic and predictive implications, and the main features of immunohistochemical markers used as surrogates to stratify BC into pre-defined molecular clusters.

Heterogenous NECTIN4 expression in urothelial high-risk non-muscle-invasive bladder cancer

High-grade non-muscle-invasive bladder cancer (HG NMIBC) patients are at high risk (HR) of progression to muscle-invasion. Bladder-preserving therapies for this patient subgroup are limited, and additional treatments are desirable. Recently, enfortumab vedotin, targeting cancer-associated NECTIN4, has been approved for the treatment of advanced urothelial carcinoma. However, data on the expression of NECTIN4 and its therapeutic potential for HR NMIBC are scarce. Here, NECTIN4 was immunohistochemically analyzed in urothelial HG NMIBC by studying cohorts of carcinoma in situ (CIS)/T1HG (N = 182 samples), HG papillary tumors from mixed-grade lesions (mixed TaHG) (N = 87) and papillary HG tumors without a history of low-grade disease (pure TaHG/T1HG) (N = 98) from overall 225 patients. Moreover, inter-lesional NECTIN4 heterogeneity in multifocal HG NMIBC tumors was determined. A high prevalence of NECTIN4 positivity was noted across HG NMIBC subgroups (91%, N = 367 samples), with 77% of samples showing moderate/strong expression. Heterogenous NECTIN4 levels were observed between HG NMIBC subgroups: non-invasive areas of CIS/T1HG and pure TaHG/T1HG samples showed NECTIN4 positivity in 96% and 99%, with 88% and 83% moderate/strong expressing specimens, respectively, whereas significantly lower NECTIN4 levels were detected in mixed TaHG lesions (72% positivity, 48% of samples with moderate/strong NECTIN4 expression). Moreover, higher NECTIN4 heterogeneity was observed in patients with multifocal mixed TaHG tumors (22% of patients) compared to patients with multifocal CIS/T1HG and pure TaHG/T1HG tumors (9% and 5%). Taken together, NECTIN4-directed antibody–drug conjugates might be promising for the treatment of HR NMIBC patients, especially for those exhibiting CIS/T1HG and pure TaHG/T1HG tumors without a history of low-grade disease.

Intratumoral heterogeneity of surrogate molecular subtypes in urothelial carcinoma in situ of the urinary bladder: implications for prognostic stratification of high-risk non-muscle-invasive bladder cancer

Reliable factors predicting the disease course of non-muscle-invasive bladder cancer (NMIBC) with carcinoma in situ (CIS) are unavailable. Molecular subtypes have potential for prognostic stratification of muscle-invasive bladder cancer, while their value for CIS patients is unknown. Here, the prognostic impact of both clinico-pathological parameters, including CIS focality, and immunohistochemistry-based surrogate subtypes was analyzed in a cohort of high-risk NMIBC patients with CIS. In 128 high-risk NMIBC patients with CIS, luminal (KRT20, GATA3, ERBB2) and basal (KRT5/6, KRT14) surrogate markers as well as p53 were analyzed in 213–231 biopsies. To study inter-lesional heterogeneity of CIS, marker expression in independent CIS biopsies from different bladder localizations was analyzed. Clinico-pathological parameters and surrogate subtypes were correlated with recurrence-free (RFS), progression-free (PFS), cancer-specific (CSS), and overall survival (OS). Forty-six and 30% of CIS patients exhibited a luminal-like (KRT20-positive, KRT5/6-negative) and a null phenotype (KRT20-negative, KRT5/6-negative), respectively. A basal-like subtype (KRT20-negative, KRT5/6-positive) was not observed. A significant degree of inter-lesional CIS heterogeneity was noted, reflected by 23% of patients showing a mixed subtype. Neither CIS surrogate subtype nor CIS focality was associated with patient outcome. Patient age and smoking status were the only potentially independent prognostic factors predicting RFS, PFS, OS, and PFS, respectively. In conclusion, further clarification of heterogeneity of surrogate subtypes in HR NMIBC and their prognostic value is of importance with regard to potential implementation of molecular subtyping into clinical routine. The potential prognostic usefulness of patient age and smoking status for high-risk NMIBC patients with CIS needs further validation.

Strategies to Get Drugs across Bladder Penetrating Barriers for Improving Bladder Cancer Therapy

Bladder cancer is a significant public health concern and social burden due to its high recurrence risk. Intravesical drug instillation is the primary therapy for bladder cancer to prevent recurrence. However, the intravesical drug therapeutic effect is limited by bladder penetrating barriers. The inadequate intravesical treatment might cause the low drug concentration in lesions, resulting in a high recurrence/progression rate of bladder cancer. Many strategies to get drugs across bladder penetrating barriers have been developed to improve intravesical treatment, including physical and chemical methods. This review summarizes the classical and updated literature and presents insights into great therapeutic potential strategies to overcome bladder penetrating barriers for improving the intravesical treatment of bladder cancer.

The double-sided effects of Mycobacterium Bovis bacillus Calmette-Guérin vaccine

Bacillus Calmette-Guérin (BCG), the only vaccine proven to be effective against tuberculosis (TB), is the most commonly used vaccine globally. In addition to its effects on mycobacterial diseases, an increasing amount of epidemiological and experimental evidence accumulated since its introduction in 1921 has shown that BCG also exerts non-specific effects against a number of diseases, such as non-mycobacterial infections, allergies and certain malignancies. Recent Corona Virus Disease 2019 (COVID-19) outbreak has put BCG, a classic vaccine with significant non-specific protection, into the spotlight again. This literature review briefly covers the diverse facets of BCG vaccine, providing new perspectives in terms of specific and non-specific protection mechanisms of this old, multifaceted, and controversial vaccine.

Value of tumour-infiltrating immune cells in predicting response to intravesical BCG in patients with non-muscle-invasive bladder cancer: a systematic review and meta-analysis

OBJECTIVE

To investigate the predictive value of tumour-infiltrating immune cells (TIICs) on oncological outcomes and response to BCG treatment in patients with non-muscle-invasive bladder cancer (NMIBC).

MATERIALS AND METHODS

A systematic review and meta-analysis was performed using PubMed, Scopus and the Cochrane Library in July 2020 to identify relevant studies according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The pooled recurrence-free survival (RFS) rate was calculated using a fixed-effect model.

RESULTS

We retrieved 15 studies (including 791 patients) evaluating the effect of TIICs on oncological outcomes in patients with NMIBC treated with intravesical BCG. TIICs were reported to be a significant predictor of oncological outcomes and response to BCG treatment in 10 studies. Tumour-associated macrophages were associated with worse RFS (pooled hazard ratio 2.30, 95% confidence interval 1.64-3.22).

CONCLUSIONS

Based on these data, TIICs are significant predictors of RFS and response to BCG treatment in patients with NMIBC; therefore, incorporation of TIICs into risk stratification models may help patients and physicians in the clinical decision-making process in order to achieve the maximum possible benefit from BCG treatment.

Pure high-grade papillary urothelial bladder cancer: a luminal-like subgroup with potential for targeted therapy

PURPOSE

Non-invasive high-grade (HG) bladder cancer is a heterogeneous disease that is characterized insufficiently. First-line Bacillus Calmette-Guérin instillation fails in a substantial amount of cases and alternative bladder-preserving treatments are limited, underlining the need to promote a further molecular understanding of non-invasive HG lesions. Here, we characterized pure HG papillary urothelial bladder cancer (pure pTa HG), a potential subgroup of non-invasive HG bladder carcinomas, with regard to molecular subtype affiliation and potential for targeted therapy.

METHODS

An immunohistochemistry panel comprising luminal (KRT20, ERBB2, ESR2, GATA3) and basal (KRT5/6, KRT14) markers as well as p53 and FGFR3 was used to analyze molecular subtype affiliations of 78 pure pTa HG/papillary pT1(a) HG samples. In 66 of these, ERBB2 fluorescence in situ hybridization was performed. Additionally, targeted sequencing (31 genes) of 19 pTa HG cases was conducted, focusing on known therapeutic targets or those described to predict response to targeted therapies noted in registered clinical trials or that are already approved.

RESULTS

We found that pure pTa HG/papillary pT1(a) HG lesions were characterized by a luminal-like phenotype associated with frequent (58% of samples) moderate to high ERBB2 protein expression, rare FGFR3 alterations on genomic and protein levels, and a high frequency (89% of samples) of chromatin-modifying gene alterations. Of note, 95% of pTa HG/papillary pT1 HG cases harbored at least one potential druggable genomic alteration.

CONCLUSIONS

Our data should help guiding the selection of targeted therapies for investigation in future clinical trials and, additionally, may provide a basis for prospective mechanistic studies of pTa HG pathogenesis.

Bacterial immunotherapy for cancer induces CD4-dependent tumor-specific immunity through tumor-intrinsic interferon-γ signaling

Bacillus Calmette-Guérin (BCG) immunotherapy for bladder cancer is the only bacterial cancer therapy approved for clinical use. Although presumed to induce T cell-mediated immunity, whether tumor elimination depends on bacteria-specific or tumor-specific immunity is unknown. Herein we show that BCG-induced bladder tumor elimination requires CD4 and CD8 T cells, although augmentation or inhibition of bacterial antigen-specific T cell responses does not alter the efficacy of BCG-induced tumor elimination. In contrast, BCG stimulates long-term tumor-specific immunity that primarily depends on CD4 T cells. We demonstrate that BCG therapy results in enhanced effector function of tumor-specific CD4 T cells, mainly through enhanced production of IFN-γ. Accordingly, BCG-induced tumor elimination and tumor-specific immune memory require tumor cell expression of the IFN-γ receptor, but not MHC class II. Our findings establish that a bacterial immunotherapy for cancer is capable of inducing tumor immunity, an antitumor effect that results from enhanced function of tumor-specific CD4 T cells, and ultimately requires tumor-intrinsic IFN-γ signaling, via a mechanism that is distinct from other tumor immunotherapies.

Transurethral needle electrode resection and transurethral holmium laser resection of bladder cancer

Purpose

The aim of the present study was to explore the efficacy and safety of transurethral needle electrode resection and transurethral holmium laser resection of non-muscular invasive bladder cancer (NMIBC).

Patients and methods

In this prospective, case-control study, patients from the Urinary Surgery or Oncology Department who met the inclusion and exclusion criteria received transurethral needle electrode resection (n = 52) or transurethral holmium laser resection (n = 51).

Results

A total of 103 patients with NMIBC were included in the present study, with 68 males and 35 females. Their mean age was 57.3 years. Sixty-two patients had Ta, 15 patients had T1, and 26 patients had Tis. Operative time, intraoperative blood loss, postoperative gross hematuria time, bladder irrigation time, and postoperative hospitalization time were all significantly lower in the transurethral holmium laser resection group than the transurethral needle electrode resection group. After resection, transurethral holmium laser resection significantly decreased the value of HGF, TSH, and TNF-α versus the transurethral needle electrode resection group. The incidence of obturator reflex was significantly lower in the transurethral holmium laser resection group than the transurethral needle electrode resection group. There was no significant difference in disease-free survival rate and progression-free survival rate between the two groups.

Conclusions

Transurethral holmium laser resection has clinical advantages in the treatment of NMIBC.

Downregulation of ST3GAL5 is associated with muscle invasion, high grade and a poor prognosis in patients with bladder cancer

In patients with bladder cancer (BC), the association between ST3 β-galactoside α-2,3-sialyltransferase 5 (ST3GAL5) expression and clinical outcomes, particularly regarding muscle-invasive disease, high tumor grade and prognosis, remain unknown. In the present study, the expression of ST3GAL5 and its association with clinical outcomes in patients with BC was analyzed using various public bioinformatics databases. The difference in ST3GAL5 expression between BC and healthy bladder tissues was also evaluated using data from the Oncomine database, The Cancer Genome Atlas and Gene Expression Omnibus database. The differences in ST3GAL5 expression between muscle invasive BC (MIBC) and non-muscle invasive BC (NMIBC), and high- and low-grade BC were also analyzed. Furthermore, genes that were positively co-expressed with ST3GAL5 in patients with BC were identified from the intersection between the Oncomine, Gene Expression Profiling Interactive Analysis 2 and UALCAN databases. Enrichment analysis by Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, Reactome pathway enrichment analyses and a gene-concept network was performed using R package. Gene set enrichment analysis was also performed to assess the signaling pathways influenced by the high and low expression of ST3GAL5 in BC. The results indicated that ST3GAL5 expression was significantly lower in BC tissues compared with normal bladder tissues (P<0.05). Furthermore, ST3GAL5 expression in MIBC and high-grade BC was significantly lower compared with NMIBC and low-grade BC (P<0.05), respectively. The results from Kaplan-Meier survival analysis result demonstrated that ST3GAL5 downregulation was associated with poor survival in patients with BC (P<0.05). Taken together, these findings suggested that ST3GAL5 may be considered as an anti-oncogene in BC, could represent a potential predictive and prognostic biomarker for BC and may be a molecular target for tumor therapy.

Combination Intravesical Therapy

After Bacillus Calmette-Guerin (BCG) failure, there is likely a 6- to 24-month window whereby salvage intravesical therapy might allow for preservation of the bladder without disease worsening. Combination intravesical, salvage therapy for nonmuscle invasive bladder cancer represents a promising avenue for treatment in patients unfit or unwilling to undergo cystectomy. BCG with concomitant immune stimulating agents or immune checkpoint inhibitors, combination chemotherapy regimens, such as gemcitabine and docetaxol, and novel agents currently in clinical trials provide hope for a bladder-sparing alternative for patients after BCG failure.

Next-Generation Sequencing Reveals Potential Predictive Biomarkers and Targets of Therapy for Urothelial Carcinoma in Situ of the Urinary Bladder

Bacillus Calmette-Guérin instillation after removal of the tumor is the first line of treatment for urothelial carcinoma in situ (CIS), the precursor lesion of most muscle-invasive bladder cancers. Bacillus Calmette-Guérin therapy fails in >50% of cases, and second-line radical cystectomy is associated with overtreatment and drastic lifestyle consequences. Given the need for alternative bladder-preserving therapies, we identified genomic alterations (GAs) in urothelial CIS having the potential to predict response to targeted therapies. Laser-capture microdissection was applied to isolate 30 samples (25 CIS and 5 muscle controls) from 26 fresh-frozen cystectomy specimens. Targeted next-generation sequencing of 31 genes was performed. The panel comprised genes frequently affected in muscle-invasive bladder cancer of nonpapillary origin, focusing on potentially actionable GAs described to predict response to approved targeted therapies or drugs that are in registered clinical trials. Of CIS patients, 92% harbored at least one potentially actionable GA, which was identified in TP53/cell cycle pathway-related genes (eg, TP53 and MDM2) in 72%, genes encoding chromatin-modifying proteins (eg, ARID1A and KDM6A) in 68%, DNA damage repair genes (eg, BRCA2 and ATM) in 60%, and phosphatidylinositol 3-kinase/mitogen-activated protein kinase pathway genes (eg, ERBB2 and FGFR1) in 36% of the cases. These data might help guide the selection of targeted therapies to be investigated in future clinical CIS trials, and they may provide a basis for future mechanistic studies of urothelial CIS pathogenesis.

Aristolochic Acid and Immunotherapy for Urothelial Carcinoma: Directions for unmet Needs

Urothelial carcinoma of the bladder (UCB) and upper tracts (UTUC) used to share management with similar principles. However, their genetic and epigenetic differences along with different responses to immunotherapy were recently identified, which are reminiscent of their distinct etiologies. Different from the variety of environmental factors relating to UCB, UTUC is best known for its close relationship with exposure to aristolochic acid (AA). AA is believed to cause its carcinogenicity through forming DNA adducts of deoxyadenosine-aristolactam, as well as A:T → T:A transversions in the TP53 tumor suppressor gene. Since recent findings suggested that cancers with higher somatic mutations are associated with better treatment responses upon immune checkpoint blockade, UTUC and AA-related biomarkers reasonably serve as good candidates, as well as a potential prognostic predictor for the flourishing immunotherapy. This review covers the current state of the literature on the clinical response of UTUC and UCB receiving immunotherapy and points out directions for refinement regarding patient selection.

In vitro Evidence of Human Immune Responsiveness Shows the Improved Potential of a Recombinant BCG Strain for Bladder Cancer Treatment

The live attenuated mycobacterial strain BCG, in use as vaccine against tuberculosis, is considered the gold standard for primary therapy of carcinoma in situ of the bladder. Despite its limitations, to date it has not been surpassed by any other treatment. Our group has developed a recombinant BCG strain expressing the detoxified S1 pertussis toxin (rBCG-S1PT) that proved more effective than wild type BCG (WT-BCG) in increasing survival time in an experimental mouse model of bladder cancer, due to the well-known adjuvant properties of pertussis toxin. Here, we investigated the capacity of rBCG-S1PT to stimulate human immune responses, in comparison to WT-BCG, using an in vitro stimulation assay based on human whole blood cells that allows for a comprehensive evaluation of leukocyte activation. Blood leukocytes stimulated with rBCG-S1PT produced increased levels of IL-6, IL-8, and IL-10 as compared to WT-BCG, but comparable levels of IL-1β, IL-2, IFN-γ, and TNF-α. Stimulation of blood cells with the recombinant BCG strain also enhanced the expression of CD25 and CD69 on human CD4+ T cells. PBMC stimulated with rBCG-S1PT induced higher cytotoxicity to MB49 bladder cancer cells than WT-BCG-stimulated PBMC. These results suggest that the rBCG-S1PT strain is able to activate an immune response in human leukocytes that is higher than that induced by WT-BCG for parameters linked to better prognosis in bladder cancer (regulation of immune and early inflammatory responses), while fully comparable to WT-BCG for classical inflammatory parameters. This establishes rBCG-S1PT as a new highly effective candidate as immunotherapeutic agent against bladder cancer.

Circulating Tumor Cells Identify Patients with Super-High-Risk Non-Muscle-Invasive Bladder Cancer: Updated Outcome Analysis of a Prospective Single-Center Trial

BACKGROUND

Clinical behavior of non-muscle-invasive bladder cancer (NMIBC) is largely unpredictable, and even patients treated according to European Association of Urology recommendations have a heterogeneous prognosis. High-grade T1 (HGT1) bladder cancer is the highest-risk subtype of NMIBC, with an almost 40% rate of recurrence and 20% of progression at 5 years. Nomograms predicting risk of recurrence, progression, and cancer-specific survival (CSS) are not available specifically within HGT1 bladder cancer, and the identification of robust prognostic biomarkers to better guide therapeutic strategies in this subgroup of patients is of paramount importance. Strategies to identify putative biomarkers in liquid biopsies from blood and urine collected from patients with bladder cancer have been intensively studied in the last few years.

SUBJECTS, MATERIALS, AND METHODS

We here report the final analysis of a single-center prospective study aimed to investigate the impact of circulating tumor cells (CTCs) on CSS and overall survival (OS) in 102 patients with HGT1 bladder cancer, in a median follow-up of 63 months.

RESULTS

We here demonstrate that the presence of even a single CTC is predictive of shorter CSS and OS, as compared with the standard predictive variables. Points of attention in this multivariable analysis are the long-term follow-up and the adequate number of outcome events.

CONCLUSION

The accurate risk stratification provided by CTCs might be essential for determining the best surveillance strategy for patients after diagnosis. A closer follow-up, an early radical surgery, or even a systemic treatment might be recommended in patients with super-high-risk non-muscle-invasive bladder cancer.

IMPLICATIONS FOR PRACTICE

Circulating tumor cells identify patients with super-high-risk non-muscle-invasive bladder cancer who require closer monitoring for local recurrence and/or progression of disease. This super-high-risk subgroup of patients might also require more aggressive treatment interventions, which should be evaluated in large prospective cohorts.