Intravesical bacillus Calmette-Guerin (BCG) in treating non-muscle invasive bladder cancer—analysis of adverse effects and effectiveness of two strains of BCG (Danish 1331 and Moscow)

A Territory-wide Study Investigating the Dose and Efficacy of Different Bacillus Calmette-Guérin Strains in Patients with Intermediate- and High-risk Non-muscle-invasive Bladder Cancer

BACKGROUND

Current European Association of Urology (EAU) guidelines support adjuvant intravesical Bacillus Calmette-Guérin (BCG) treatment after Transurethral Resection of Bladder Tumor (TURB) for intermediate- or high-risk Non-Muscle-Invasive Bladder Cancer (NMIBC) patients, aiming to reduce the risk of tumor recurrence. The quality of data, however, does not allow definitive conclusions on whether different strains and dosages of BCG have different efficacies on long-term survival outcomes.

OBJECTIVE

To evaluate the long-term survival outcomes of different strains and dosages of BCG in patients with NMIBC.

DESIGN, SETTING, AND PARTICIPANTS

All NMIBC patients treated with intravesical BCG therapy from 2001 to 2020 were identified using a territory-wide database in Hong Kong.

INTERVENTION

BCG strains and dosages (Connaught strain 81 mg, Connaught strain 27 mg, Tokyo strain 80 mg, and Danish strain 30 mg) were retrieved from medical records.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Overall Survival (OS), Cancer-Specific Survival (CSS), Recurrence-Free Survival (RFS), and Progression-Free Survival (PFS) were analyzed using the Kaplan-Meier method. A multivariable Cox regression analysis was used to adjust potential confounding factors, and to estimate Hazard Ratio (HR) and 95% confidence interval (CI) of different BCG strains. A further subgroup analysis on adequate versus inadequate BCG treatment was performed.

RESULTS AND LIMITATIONS

A total of 2602 NMIBC patients treated with intravesical BCG were identified. Among them, 1291 (49.6%) received Connaught strain 81 mg, 199 (7.6%) received Connaught strain 27 mg, 1014 (39.0%) received Tokyo strain, and 98 (3.8%) received Danish strain. The median follow-up was 11.0 years. No statistically significant differences in OS, CSS, RFS, and PFS were detected among the different groups. At the multivariable analysis, the Connaught strain 27 mg group was inferior to the Connaught strain 81 mg group in terms of OS (HR: 1.26, 95% CI: 1.05-1.51), CSS (HR: 1.69, 95% CI: 1.08-2.66), and PFS (HR: 1.86, 95% CI: 1.20-2.88). Adequate BCG treatment was associated with improved OS (HR: 0.82, 95% CI: 0.73-0.92), CSS (HR: 0.64, 95% CI: 0.47-0.86), RFS (HR: 0.80, 95% CI: 0.70-0.92), and PFS (HR: 0.52, 95% CI: 0.39-0.68). Among patients treated with adequate BCG, at the multivariable analysis the Connaught strain 27 mg group showed worse results than the Connaught strain 81 mg group in terms of CSS (HR: 1.93, 95% CI: 1.07-3.51). Compared with the Connaught strain 81 mg group, both Tokyo and Danish strains had similar survival outcomes in the whole cohort and the adequate BCG treatment subgroup.

CONCLUSIONS

Our findings suggest that adequate BCG remains the most important factor in optimizing survival outcomes in patients with intermediate- and high-risk NMIBC. No significant differences in survival outcomes were observed between full-dose Connaught, Tokyo, and Danish strains. Reduced-dose Connaught strain was associated with the worst survival outcomes.

PATIENT SUMMARY

We evaluated the efficacy of different strains and dosages of bacillus Calmette-Guérin (BCG) in patients with intermediate- or high-risk non-muscle-invasive bladder cancer in the past two decades in Hong Kong. We conclude no significant differences in long-term survival outcomes in terms of full-dose Connaught, Tokyo, and Danish strains, while reduced-dose Connaught strain was inferior to the full-dose group. Adequate BCG treatment benefits long-term survival.

BCG induced lower urinary tract symptoms during treatment for NMIBC-Mechanisms and management strategies

Non-muscle invasive bladder cancer (NMIBC) accounts for ~70-75% of total bladder cancer tumors and requires effective early intervention to avert progression. The cornerstone of high-risk NMIBC treatment involves trans-urethral resection of the tumor followed by intravesical Bacillus Calmette-Guerin (BCG) immunotherapy. However, BCG therapy is commonly accompanied by significant lower urinary tract symptoms (LUTS) including urinary urgency, urinary frequency, dysuria, and pelvic pain which can undermine treatment adherence and clinical outcomes. Despite this burden, the mechanisms underlying the development of BCG-induced LUTS have yet to be characterized. This review provides a unique perspective on the mechanisms thought to be responsible for the development of BCG-induced LUTS by focussing on the sensory nerves responsible for bladder sensory transduction. This review focuses on how the physiological response to BCG, including inflammation, urothelial permeability, and direct interactions between BCG and sensory nerves could drive bladder afferent sensitization leading to the development of LUTS. Additionally, this review provides an up-to-date summary of the latest clinical data exploring interventions to relieve BCG-induced LUTS, including therapeutic targeting of bladder contractions, inflammation, increased bladder permeability, and direct inhibition of bladder sensory signaling. Addressing the clinical burden of BCG-induced LUTS holds significant potential to enhance patient quality of life, treatment compliance, and overall outcomes in NMIBC management. However, the lack of knowledge on the pathophysiological mechanisms that drive BCG-induced LUTS has limited the development of novel and efficacious therapeutic options. Further research is urgently required to unravel the mechanisms that drive BCG-induced LUTS.

Novel immunotherapeutic options for BCG-unresponsive high-risk non-muscle-invasive bladder cancer

BACKGROUND

High-risk non-muscle-invasive bladder cancer (HR-NMIBC) presents a challenge to many physicians due to its ability to resist Bacillus Calmette-Guérin (BCG) intravesical therapy and the substantial rate of progression into muscle-invasive bladder cancer (MIBC). Patients who are BCG-unresponsive have worse prognosis and thus require further management including radical cystectomy (RC), which significantly impacts quality of life. Moreover, the ongoing worldwide shortage of BCG warrants the need for policies that prioritize drug use and utilize alternative treatment strategies. Hence, there is a significant unmet need for bladder preserving therapy in this subset of patients.

METHODS

To address this issue, we searched the relevant literature in PUBMED for articles published from 2019 through May of 2023 using appropriate keywords. All clinical trials of patients with HR-NMIBC treated with immune-related agents were retrieved from clinicaltrials.gov.

FINDINGS AND FUTURE PERSPECTIVES

Exploratory treatments for BCG-Unresponsive HR-NMIBC included immune checkpoint inhibitors (ICI), oncolytic viral therapy, cytokine agonists, and other immunomodulators targeting TLR, EpCaM, FGFR, MetAP2, and IDO1. Some combination therapies have been found to work synergistically and are preferred therapeutically over monotherapy. Three drugs-pembrolizumab, valrubicin, and most recently, nadofaragene firadenovec-vncg-have been FDA approved for the treatment of BCG-unresponsive NMIBC in patients who are ineligible for or decline RC. However, all explored treatment options tend to postpone RC rather than provide long-term disease control. Additional combination strategies need to be studied to enhance the effects of immunotherapy. Despite the challenges faced in finding effective therapies, many potential treatments are currently under investigation. Addressing the landscape of biomarkers, mechanisms of progression, BCG resistance, and trial design challenges in HR-NMIBC is essential for the discovery of new targets and the development of effective treatments.

Current and Emerging Treatments for Urothelial Carcinoma: A Focus on Enfortumab Vedotin

Urothelial carcinoma is a common malignancy that affects the urinary system, with bladder cancer being the most prevalent form. Although the management of early-stage disease has seen significant improvements, the treatment of locally advanced and metastatic urothelial carcinoma remains challenging. Over the past decade, there has been an explosion in the number of therapies available for the treatment of advanced disease, with immune checkpoint inhibitors and antibody-drug conjugates leading the way. Enfortumab vedotin is an antibody-drug conjugate that targets Nectin-4, a protein that is overexpressed in urothelial carcinoma cells. In clinical trials, it has shown promising outcomes for the treatment of advanced urothelial carcinoma that has progressed after chemotherapy or immunotherapy. The US Food and Drug Administration has granted expedited approval for enfortumab vedotin in the treatment of advanced urothelial carcinoma. This review provides an overview of the current and emerging treatments for urothelial carcinoma, with a particular focus on enfortumab vedotin. We discuss the mechanisms of action, clinical efficacy, safety, and ongoing research of enfortumab vedotin, along with the current landscape of other approved therapies and promising agents in development. The aim of this review is to provide a comprehensive and up-to-date summary of the available treatment options for urothelial carcinoma, including their limitations and future prospects.

Values of OAS gene family in the expression signature, immune cell infiltration and prognosis of human bladder cancer

Background

Bladder cancer (BLCA) is one of the most common genitourinary malignancies in the world, but its pathogenic genes have not been fully identified and the treatment outcomes are still unsatisfactory. Although the members of 2', 5'-oligoadenylate synthetase (OAS) gene family are known involved in some tumorous biological processes, the roles of the OAS gene family in BLCA are still undetermined.

Methods

By combining vast bioinformatic datasets analyses of BLCA and the experimental verification on clinical BLCA specimen, we identified the expressions and biological functions of OAS gene family members in BLCA with comparison to normal bladder tissues.

Results

The expression levels of OAS gene family members were higher in BLCA than in normal bladder tissues. The expression levels of most OAS genes had correlations with genomic mutation and methylation, and with the infiltration levels of CD4 + T cells, CD8 + T cells, neutrophils, and dendritic cells in the microenvironment of BLCA. In addition, high expressions of OAS1, OAS2, OAS3, and OASL predicted better overall survival in BLCA patients.

Conclusions

The highly expressed OAS genes in BLCA can reflect immune cells infiltration in the tumor microenvironment and predict the better overall survival of BLCA, and thus may be considered as a signature of BLCA. The study provides new insights into the diagnosis, treatment, and prognosis of BLCA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-10102-8.