Bacillus Calmette–Guérin‐unresponsive non‐muscle‐invasive bladder cancer: Its definition and future therapeutic strategies

Recent advancements in the diagnosis and treatment of non-muscle invasive bladder cancer: Evidence update of surgical concept, risk stratification, and BCG-treated disease

In the management of non-muscle invasive bladder cancer (NMIBC), disease progression and long-term control are determined by the intensity of delivered treatment and surveillance and the cancer cells' biological nature. This requires risk stratification-based postoperative management, such as intravesical instillation of chemotherapy drugs, Bacillus Calmette-Guérin (BCG), and radical cystectomy. Advancements in mechanical engineering, molecular biology, and surgical skills have evolved the clinical management of NMIBC. In this review, we describe the updated evidence and perspectives regarding the following aspects: (1) advancements in surgical concepts, techniques, and devices for transurethral resection of the bladder tumor; (2) advancements in risk stratification tools for NMIBC; and (3) advancements in treatment strategies for BCG-treated NMIBC. Repeat transurethral resection, en-bloc transurethral resection, and enhanced tumor visualization, including photodynamic diagnosis and narrow-band imaging, help reduce residual cancer cells, provide accurate diagnosis and staging, and sensitive detection, which are the first essential steps for cancer cure. Risk stratification should always be updated and improved because the treatment strategy changes over time. The BCG-treated disease concept has recently diversified to include BCG failure, resistance, refractory, unresponsiveness, exposure, and intolerance. A BCG-unresponsive disease is an extremely aggressive subset unlikely to respond to a rechallenge with BCG. Numerous ongoing clinical trials aim to develop a future bladder-sparing approach for very high-risk BCG-naïve NMIBC and BCG-unresponsive NMIBC. The key to improving the quality of patient care lies in the continuous efforts to overcome the clinical limitations of bedside management.

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.

Tumour microenvironment as a predictive factor for immunotherapy in non-muscle-invasive bladder cancer

Bladder cancer (BC) can be divided into two subgroups depending on invasion of the muscular layer: non-muscle-invasive bladder cancer (NMIBC) and muscle-invasive bladder cancer (MIBC). Its aggressiveness is associated, inter alia, with genetic aberrations like losses of 1p, 6q, 9p, 9q and 13q; gain of 5p; or alterations in the p53 and p16 pathways. Moreover, there are reported metabolic disturbances connected with poor diagnosis-for example, enhanced aerobic glycolysis, gluconeogenesis or haem catabolism.Currently, the primary way of treatment method is transurethral resection of the bladder tumour (TURBT) with adjuvant Bacillus Calmette-Guérin (BCG) therapy for NMIBC or radical cystectomy for MIBC combined with chemotherapy or immunotherapy. However, intravesical BCG immunotherapy and immune checkpoint inhibitors are not efficient in every case, so appropriate biomarkers are needed in order to select the proper treatment options. It seems that the success of immunotherapy depends mainly on the tumour microenvironment (TME), which reflects the molecular disturbances in the tumour. TME consists of specific conditions like hypoxia or local acidosis and different populations of immune cells including tumour-infiltrating lymphocytes, natural killer cells, neutrophils and B lymphocytes, which are responsible for shaping the response against tumour neoantigens and crucial pathways like the PD-L1/PD-1 axis.In this review, we summarise holistically the impact of the immune system, genetic alterations and metabolic changes that are key factors in immunotherapy success. These findings should enable better understanding of the TME complexity in case of NMIBC and causes of failures of current therapies.

Global research trends in non-muscle invasive bladder cancer: Bibliometric and visualized analysis

BACKGROUND

Bladder cancer is one of the most common urological cancers. Non-muscle invasive bladder cancer (NMIBC) accounts for about 75-85% of all newly diagnosed bladder cancers. Globally, there are many NMIBC-related publications. However, a bibliometric analysis of these publications has not been performed.

OBJECTIVE

This study aims to systematically analyze and visualize NMIBC-related publications through bibliometrics, and to reveal identified topics, hotspots, and knowledge gaps in related fields.

METHODS

Based on the Web of Science core collection database, we firstly analyzed the quantity and quality of publications in the field of NMIBC, secondly profiled the publishing groups in terms of country, institution, author's publication and cooperation network, and finally sorted out and summarized the hot topics of research.

RESULTS

This bibliometric analysis was conducted from 2001 to 2022. The analysis identified 2,185 articles and reviews, which were published in 402 journals. The number of publications and citations on NMIBC-related research has steadily increased over the last two decades. Furthermore, academic institutions in Europe and the United States play a leading role in NMIBC research. The country, institution, journal, and author with the most publications were the United States (559), Radboud University Nijmegen (88), Urologic oncology: Seminars and Original Investigations (141), and Witjes J (74), respectively. The most frequently used keywords were Bladder cancer (793), Recurrence (671), Urothelial carcinoma (593), Progression (523), Bacillus-calmette-guerin (411), Transitional-cell carcinoma (401), Carcinoma (366), Risk (297), Transurethral resection (286), and Non-muscle-invasive bladder cancer (280).

CONCLUSION

More and more scholars are devoted to the research of related NMIBC. This bibliometric analysis revealed that the main research topics and hotspots in NMIBC included pathological staging, clinical diagnosis and treatment, and bladder perfusion.

FGFBP1 as a potential biomarker predicting bacillus Calmette–Guérin response in bladder cancer

Accurate prediction of Bacillus Calmette–Guérin (BCG) response is essential to identify bladder cancer (BCa) patients most likely to respond sustainably, but no molecular marker predicting BCG response is available in clinical routine. Therefore, we first identified that fibroblast growth factor binding protein 1 (FGFBP1) was upregulated in failures of BCG therapy, and the increased FGFBP1 had a poor outcome for BCa patients in the E-MTAB-4321 and GSE19423 datasets. These different expression genes associated with FGFBP1 expression are mainly involved in neutrophil activation, neutrophil-mediated immunity, and tumor necrosis factor-mediated signal pathways in biological processes. A significant positive correlation was observed between FGFBP1 expression and regulatory T-cell (Treg) infiltration by the Spearman correlation test in the BCG cohort (r = 0.177) and The Cancer Genome Atlas (TCGA) cohort (r = 0.176), suggesting that FGFBP1 may influence the response of BCa patients to BCG immunotherapy through immune escape. Though FGFBP1 expression was positively correlated with the expressions of PD-L1, CTLA4, and PDCD1 in TCGA cohort, a strong association between FGFBP1 and PD-L1 expression was only detected in the BCG cohort (r = 0.750). Furthermore, elevated FGFBP1 was observed in BCa cell lines and tissues in comparison to corresponding normal controls by RT-qPCR, Western blotting, and immunohistochemical staining. Increased FGFBP1 was further detected in the failures than in the responders by immunohistochemical staining. Notably, FGFBP1 is positively associated with PD-L1 expression in BCa patients with BCG treatment. To sum up, FGFBP1 in BCa tissue could be identified as a promising biomarker for the accurate prediction of BCG response in BCa.

Emerging treatment landscape of non-muscle invasive bladder cancer

INTRODUCTION

Non-muscle invasive bladder cancer (NMIBC) accounts for 70-75% of all bladder cancers and is a heterogeneous disease characterized by a wide spectrum of recurrences and progression. Adjuvant treatment for intermediate- and high-risk NMIBC is mainly represented by Bacillus Calmette Guerin (BCG). However, 20%-40% of patients develop disease recurrences or persistence following BCG treatment and are classified as "BCG unresponsive' (BCGu), thus representing a therapeutic challenge due to their worse prognosis and unavailability of effective intravesical treatments.

AREAS COVERED

We provide an overview of completed and ongoing clinical trials assessing the role of innovative immunological and target agents in patients with BCGu and BCG naive (BCGn) NMIBCs. New treatment options are emerging, demonstrating promising clinical activity, namely, pembrolizumab, atezolizumab, oportuzumab monatox, nadofaragene firadenovec, and N-803.

EXPERT OPINION

The increasing number of newer therapeutic agents for patients with NMIBC poses challenges regarding the choice of the most suited treatment option for each patient and the best treatment sequence, given their diverse mechanisms of action and varying degrees of activity. Tailored treatment approaches are advocated, based on a deeper comprehension of disease features, available therapies, patient's characteristics, and consequently, on the identification and validation of prognostic and predictive biomarkers.

Single immediate instillation of chemotherapy is associated with decreased recurrence and progression in patients with high-risk non-muscle-invasive bladder cancer who receive adjuvant induction bacillus Calmette-Guérin therapy

OBJECTIVES

To investigate whether a single intravesical instillation of chemotherapy is associated with improved oncological outcomes in patients with high-risk non-muscle-invasive bladder cancer who receive adjuvant induction bacillus Calmette-Guérin therapy.

METHODS

This multi-institutional retrospective study included 205 patients with high-risk non-muscle-invasive bladder cancer who received adjuvant induction bacillus Calmette-Guérin therapy. Patients were divided into two groups: those who received the combined therapy of a single instillation of chemotherapy plus subsequent adjuvant induction bacillus Calmette-Guérin therapy (combined therapy group), and those who received adjuvant induction bacillus Calmette-Guérin therapy alone (bacillus Calmette-Guérin monotherapy group). Multivariable analyses using the inverse probability of treatment weighting method and Fine-Gray competing risk regression models were performed to evaluate the impact of a single instillation of chemotherapy on intravesical recurrence-free survival and muscle-invasive bladder cancer-free survival.

RESULTS

Among the 205 patients, 130 (63%) and 75 (37%) were classified as the combined therapy and bacillus Calmette-Guérin monotherapy groups, respectively. Multivariable analyses using the inverse probability of treatment weighting method showed that a single instillation of chemotherapy was significantly associated with longer intravesical recurrence-free survival (hazard ratio 0.279; P < 0.001) and muscle-invasive bladder cancer-free survival (hazard ratio 0.078; P < 0.001). Fine-Gray competing risk regression model revealed that a single instillation of chemotherapy was associated with a significantly lower probability of intravesical recurrence and muscle-invasive bladder cancer progression, with an adjusted subdistribution hazard ratio of 0.477 (P = 0.008) and 0.261 (P = 0.043), respectively.

CONCLUSION

A single intravesical instillation of chemotherapy may be a potential treatment option in patients with high-risk non-muscle-invasive bladder cancer who receive adjuvant induction bacillus Calmette-Guérin therapy.

Multi-country clinical practice patterns, including use of biomarkers, among physicians’ treatment of BCG-unresponsive non-muscle invasive bladder cancer (NMIBC)

Background

Intravesical bacillus Calmette-Guérin (BCG) fails in a considerable proportion of non-muscle invasive bladder cancer (NMIBC) patients despite treatment per recommended protocol. This real-world study aimed to understand the current patterns of treatment and disease management for the broad BCG-unresponsive NMIBC patient population, alongside collecting sufficient data on patients who do not undergo cystectomy.

Methods

This was a multicenter, retrospective survey of physicians treating BCG-unresponsive NMIBC patients. Data were collected in eight countries – France, Germany, Spain, Italy, United Kingdom, United States, China, and Japan – between January and May 2019. The study consisted of a short online physician survey and a retrospective chart review of eligible BCG-unresponsive NMIBC patients. Physicians abstracted chart data for the last 10 (five patients in Japan) eligible BCG-unresponsive NMIBC patients meeting the inclusion criteria, and the data were analysed for all countries combined using descriptive statistics. Country-specific analyses were also carried out, as appropriate.

Results

Overall, 508 physicians participated in the study. Almost one-quarter (22.9%) of physicians’ current NMIBC patient caseload was BCG-unresponsive, whereby BCG therapy was no longer considered an option. Half of physicians (49.4%) did not regularly use biomarker tests in their practice, with particularly few physicians undertaking biomarker testing in Spain and Japan. Biomarker testing varied considerably, with the proportions of physicians selecting ‘none’ ranging from 11.4% in China to 70.3% in Japan. Physicians reported transurethral resection of the bladder tumor (TURBT) and BCG as the most common current treatments received by their patients. Chemotherapy and anti-PD-L1 treatment options were considered impactful new therapies by 94.7% and 90.0% of physicians surveyed in this study, respectively.

Conclusions

The most common treatments received by patients in this study were TURBT and BCG. Emerging new treatments are driven by exploring biomarkers, but in real-world clinical practice only half of physicians or fewer regularly tested their NMIBC patients for biomarkers; PD-1/PD-L1 was the most common biomarker test used. Most physicians reported that, in addition to chemotherapy, anti-PD-L1 was an impactful new therapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12894-022-00959-z.

Treatment and disease management patterns for bacillus Calmette–Guérin unresponsive nonmuscle invasive bladder cancer in North America, Europe and Asia

Background

Materials and methods

Results

Conclusions

Pyuria as a Predictive Marker of Bacillus Calmette-Guérin Unresponsiveness in Non-Muscle Invasive Bladder Cancer

This study aims to investigate the clinical role of preoperative pyuria for predicting bacillus Calmette-Guérin (BCG) unresponsiveness in non-muscle invasive bladder cancer (NMIBC). We performed a logistic regression analysis on 453 patients with NMIBC who were treated with BCG immunotherapy after a transurethral resection of bladder tumours, to evaluate predictive factors of BCG unresponsiveness. We also analysed univariate and multivariable survival data to estimate the prognostic impact of pyuria. Of the total study population, 37.6% (170/453) of patients had BCG unresponsiveness. A multivariable logistic regression analysis revealed that a history of upper urinary tract cancer (odds ratio (OR): 1.86, 95% confidence interval (CI): 1.04-3.32, p-value = 0.035) and the presence of pyuria (OR: 1.51, 95% CI: 1.01-2.27, p = 0.047) and tumour multiplicity (OR: 1.80, 95% CI: 1.18-2.75, p-value < 0.001) were significant predictors of BCG unresponsiveness. A Cox proportional hazards analysis model showed that pyuria was a significant prognostic factor for progression-free survival (hazard ratio: 4.51, 95% CI: 1.22-16.66, p = 0.024). A history of upper urinary tract cancer and the presence of pyuria and tumour multiplicity are predictive markers of BCG unresponsiveness. For patients with NMIBC who have preoperative pyuria, treatment using BCG should be considered cautiously.

Bacillus Calmette-Guérin-unresponsive non-muscle invasive bladder cancer outcomes in patients without radical cystectomy

BACKGROUND

Bacillus Calmette-Guérin (BCG)-unresponsive non-muscle invasive bladder cancer (NMIBC) is a newly defined subtype that is unlikely to benefit from BCG rechallenge. Radical cystectomy is currently recommended for BCG-unresponsive NMIBC; however, a certain proportion of these patients can be managed with treatments other than that. Herein, we conducted a multicenter retrospective study to analyze the clinical outcomes of BCG-unresponsive NMIBC patients who did not receive radical cystectomy.

METHODS

Of the 141 BCG-unresponsive NMIBC patients, 94 (66.7%) received treatment except radical cystectomy. Survival outcomes were calculated from the date of diagnosis using the Kaplan-Meier method and compared using the log-rank test. Prognostic factors were identified using the multivariate Cox regression model. This group was further classified into three groups according to the number of risk factors, and survival outcomes were compared.

RESULTS

Multivariate analyses identified low estimated glomerular filtration rate (< 45 ml/min/1.73 m²) and large tumor size (≥ 30 mm) before BCG induction as independent poor prognostic factors for progression-free survival and overall survival, while the latter was also an independent factor for cancer-specific survival. The presence of variant histology was an independent poor prognostic factor for overall survival. The high-risk non-cystectomy group showed a significantly poor prognosis for progression-free survival (hazard ratio: 7.61, 95% confidence interval: 2.11-27.5), cancer-specific survival (10.4, 0.54-70.02), and overall survival (8.28, 1.82-37.7).

CONCLUSIONS

Our findings suggest that patients with renal impairment and large tumors should undergo radical cystectomy if the complications and intentions of the patients allow so.

Population-based analysis of perioperative chemotherapy use, interventions requiring hospitalization and atheroembolic events among patients with non-metastatic muscle-invasive bladder cancer

Introduction

Utilization of neoadjuvant chemotherapy (NC) in muscle invasive bladder cancer (MIBC) is increasingly recognized as standard of care but trends of use in Ontario remain unknown. Currently, there remains knowledge gaps regarding the effects of perioperative chemotherapy on the rates of interventions requiring hospitalization (IRH) and atheroembolic events (ATEs).

Methods

We conducted a population‐based retrospective study within the province of Ontario over 16 years. Patients with non‐metastatic MIBC receiving surgery only or planned for perioperative chemotherapy were included. Primary outcomes included 2‐year IRH and ATE rates. Univariate/multivariate analysis was used to identify predictors associated with IRHs and ATEs. Cochrane‐Armitage was used to assess treatment trends over time.

Results

Our study included 3281 patients. RC alone occurred in 2030 (60.9%), NC in 974 (29.6%) and adjuvant chemotherapy in 8.4% (n = 277). A total of 490/974 (50.3%) patients whom initiated NC with RC intent failed to undergo RC. This improved to 20.5% by 2015 (p < 0.001). Use of NC increased by an absolute value of 33% (p < 0.001). Overall, 4.2% of patients experienced IRHs and 11.5% ATEs. On multivariate analysis, advanced age and Charlson index score (CI) were strong predictors of outcomes, not timing of perioperative chemotherapy (p < 0.05.)

Conclusion

A total of 29.6% of MIBC patients are planned for NC with 20.5% not progressing to their surgery. Use of NC has substantially increased over time. IRHs and ATEs remain stubbornly high at 4.2% and 11.5% respectively. Older age and higher CI scores are the strongest predictors of IRHs and ATEs (p < 0.05), not perioperative chemotherapy.

New immunotherapies for high-risk non-muscle invasive bladder cancer: Current state and future perspectives

BACKGROUND

The standard treatment for high-risk non-muscle invasive bladder tumors (NMIBT) is transurethral resection of the bladder and BCG instillations. However, responses are limited, and new therapeutic alternatives for these patients are required. The results of checkpoint inhibitors in advanced tumors have led to interest in the use of these molecules in NMIBT.

METHODS

We conducted a search on PubMed using the terms «bladder cancer» and «check point inhibitors». We have used the search engines clinicaltrials.gov and clinicaltrialsregister.eu for the search of clinical trials.

RESULTS

There are currently 5 trials in progress on BCG untreated patients. There are no results available. As for BCG non-responders, there are 15 ongoing trials, two of them with preliminary results: Keynote 057, with promising results with pembrolizumab, which has led the FDA to approve its use in January 2020, and SWOG S1605, which has shown similar results with atezolizumab. Other trials are using intravesical administration of these drugs, which is an attractive option if it is effective for cancer control.

CONCLUSIONS

Checkpoint inhibitors offer a new possibility for patients who do not respond to BCG. These will probably be used in the future for previously BCG untreated patients. Preliminary data from clinical trials show promising results. A good understanding of these molecules by urologists and the creation of multidisciplinary teams are crucial in order to offer the best therapeutic alternatives to these patients.

Efficacy and safety of Bacillus Calmette-Guerin for bladder cancer: A protocol of systematic review

BACKGROUND

This study will systematically assess the efficacy and safety of Bacillus Calmette-Guerin (BCG) for patients with bladder cancer (BC).

METHODS

Literature searches will be performed in multiple electronic databases from inception to present: MEDLINE, EMBASE, CINAHL, Science Direct, Cochrane Library, Web of Science, and China National Knowledge Infrastructure. We will also examine grey literature through identifying conference proceedings, thesis, dissertations, and website of clinical trials registry. Two investigators will independently scan all citation titles, abstracts, and full-text studies. The study quality will be assessed by Cochrane Risk of Bias Tool. If possible, we will perform meta-analysis. Additional analyses will be carried out to test the potential sources of heterogeneity among included trials.

RESULTS

The present study will summarize high quality trials on investigating the efficacy and safety of BCG for patients with BC.

CONCLUSION

The results of this study will supply helpful evidence to determine whether BCG is effective or not for BC.

STUDY REGISTRATION NUMBER

INPLASY202070042.