Intravesical bacillus Calmette-Guérin for bladder cancer: are all the strains equal?

Multi-omics analysis reveals that linoleic acid metabolism is associated with variations of trained immunity induced by distinct BCG strains

Trained immunity is one of the mechanisms by which BCG vaccination confers persistent nonspecific protection against diverse diseases. Genomic differences between the different BCG vaccine strains that are in global use could result in variable protection against tuberculosis and therapeutic effects on bladder cancer. In this study, we found that four representative BCG strains (BCG-Russia, BCG-Sweden, BCG-China, and BCG-Pasteur) covering all four genetic clusters differed in their ability to induce trained immunity and nonspecific protection. The trained immunity induced by BCG was associated with the Akt-mTOR-HIF1α axis, glycolysis, and NOD-like receptor signaling pathway. Multi-omics analysis (epigenomics, transcriptomics, and metabolomics) showed that linoleic acid metabolism was correlated with the trained immunity-inducing capacity of different BCG strains. Linoleic acid participated in the induction of trained immunity and could act as adjuvants to enhance BCG-induced trained immunity, revealing a trained immunity-inducing signaling pathway that could be used in the adjuvant development.

Role of Intravesical BCG as a Therapeutic Vaccine for Treatment of Bladder Carcinoma

Bacterial products have attracted much attention as potential antitumor agents, with the ability to provide direct tumoricidal effects, leading to the inhibition of tumor growth. Treatment of superficial bladder cancer with intravesical Bacillus Calmette-Guérin (BCG) has a more reduction potential than surgery in tumor recurrence rate. BCG, the gold standard for nonmuscle invasive bladder cancer, is manufactured from different strains and produced commercially with varied strengths. There are a few countries known as the manufacturer of this strategic biopharmaceutical product, and Iran as a member of the Eastern Mediterranean Region plays a vital role in supplying this vaccine. Studies have failed to uncover the exact mechanism of action of the intravesical; however, evidence points toward an immunogenic mechanism that proficiently modifies a biologic response and provokes the immune cells in order to kill and suppress tumors. Among various underlying mechanisms, BCG bacillus attachment to fibronectin through its fibronectin attachment protein is a pivotal mechanism for BCG tumoricidal activity.

Low-dose versus standard-dose bacille Calmette–Guérin for non-muscle-invasive bladder cancer: Systematic review and meta-analysis of randomized controlled trials

Purpose

Intravesical BCG (bacille Calmette–Guérin) instillation in patients with non-muscle-invasive bladder cancer decreases the risk for tumor recurrence and progression. After one BCG product was discontinued, a chronic global BCG shortage occurred. We focused on identifying a reduced dose of BCG that could maintain efficacy and reduce adverse effects.

Materials and Methods

We conducted a comprehensive literature search of PubMed, Embase, the Cochrane Library, CINAHL, Web of Science, and Scopus to identify randomized controlled trials through April 2021. The odds ratios (ORs) and 95% confidence intervals (CIs) for the low and standard doses in nine studies were compared. A low dose was defined as a low volume of BCG compared with the standard BCG dose (Armand Frappier, 120 mg; Connaught, 81 mg; Danish 1331, 120 mg; modified Danish 1331, 120 mg; Tokyo 172, 80 mg).

Results

The low-dose group experienced aggravated recurrence (OR, 1.45; 95% CI, 1.09–1.94; p=0.01) but similar progression (OR, 1.11; 95% CI, 0.76–1.62; p=0.59), similar cancer-specific survival (OR, 1.02; 95% CI, 0.60–1.75; p=0.93), similar overall survival (OR, 1.09; 95% CI, 0.76–1.56; p=0.65), favorable adverse effects (OR, 0.41; 95% CI, 0.28–0.62; p<0.0001), and favorable withdrawal (OR, 0.42; 95% CI, 0.25–0.71; p=0.001).

Conclusions

Low-dose BCG had more unfavorable outcomes than did standard-dose BCG in terms of recurrence. Tumor progression, cancer-specific survival, and overall survival were similar between the doses. Low-dose BCG improved adverse effects and withdrawal. In the setting of BCG shortage, low-dose BCG may have strong potential as an alternative.

Intravesical High Dose BCG Tokyo and Low Dose BCG Tokyo with GMCSF+IFN α Induce Systemic Immunity in a Murine Orthotopic Bladder Cancer Model

This study evaluates a short therapy schedule for bladder cancer using BCG Tokyo. BCG Tokyo was evaluated in vitro using bone marrow derived dendritic cells, neutrophils, RAW macrophages and the murine bladder cancer cell line, MB49PSA, and compared to other BCG strains. BCG Tokyo > BCG TICE at inducing cytokine production. In vivo, high dose (1 × 10⁷ colony forming units (cfu)) and low dose (1 × 10⁶ cfu) BCG Tokyo with and without cytokine genes (GMCSF + IFNα) were evaluated in C57BL/6J mice (n = 12–16 per group) with orthotopically implanted MB49PSA cells. Mice were treated with four instillations of cytokine gene therapy and BCG therapy. Both high dose BCG alone and low dose BCG combined with cytokine gene therapy were similarly effective. In the second part the responsive groups, mice (n = 27) were monitored by urinary PSA analysis for a further 7 weeks after therapy cessation. More mice were cured at day 84 than at day 42 confirming activation of the immune system. Cured mice resisted the re-challenge with subcutaneous tumors unlike naïve, age matched mice. Antigen specific T cells recognizing BCG, HY and PSA were identified. Thus, fewer intravesical instillations, with high dose BCG Tokyo or low dose BCG Tokyo with GMCSF + IFNα gene therapy, can induce effective systemic immunity.

Immunotherapy for non-muscle-invasive bladder cancer: from the origins of BCG to novel therapies

Supplies of intravesical Bacillus Calmette-Guérin (BCG), the first-line treatment for most intermediate- and high-risk non-muscle-invasive bladder cancers (NMIBC), have proven unreliable over the past decade. This review considers the evolution of BCG immunotherapy for NMIBC: from the discovery of the antitumour side effects of tuberculosis and subsequently the BCG vaccine, to recent advances in novel immunotherapeutic agents. We summarize the evidence for alternative options to standard intravesical BCG therapy regimens and describe the potential for immune response manipulating drugs in the treatment of NMIBC. These new agents, including immune checkpoint inhibitors, toll-like receptor agonists and recombinant viral vectors, may provide better options in the management of NMIBC in the future.

Association of patients' sex with treatment outcomes after intravesical bacillus Calmette-Guérin immunotherapy for T1G3/HG bladder cancer

Purpose

To investigate the association of patients’ sex with recurrence and disease progression in patients treated with intravesical bacillus Calmette–Guérin (BCG) for T1G3/HG urinary bladder cancer (UBC).

Materials and methods

We analyzed the data of 2635 patients treated with adjuvant intravesical BCG for T1 UBC between 1984 and 2019. We accounted for missing data using multiple imputations and adjusted for covariate imbalance between males and females using inverse probability weighting (IPW). Crude and IPW-adjusted Cox regression analyses were used to estimate the hazard ratios (HR) with their 95% confidence intervals (CI) for the association of patients’ sex with HG-recurrence and disease progression.

Results

A total of 2170 (82%) males and 465 (18%) females were available for analysis. Overall, 1090 (50%) males and 244 (52%) females experienced recurrence, and 391 (18%) males and 104 (22%) females experienced disease progression. On IPW-adjusted Cox regression analyses, female sex was associated with disease progression (HR 1.25, 95%CI 1.01–1.56, p = 0.04) but not with recurrence (HR 1.06, 95%CI 0.92–1.22, p = 0.41). A total of 1056 patients were treated with adequate BCG. In these patients, on IPW-adjusted Cox regression analyses, patients’ sex was not associated with recurrence (HR 0.99, 95%CI 0.80–1.24, p = 0.96), HG-recurrence (HR 1.00, 95%CI 0.78–1.29, p = 0.99) or disease progression (HR 1.12, 95%CI 0.78–1.60, p = 0.55).

Conclusion

Our analysis generates the hypothesis of a differential response to BCG between males and females if not adequately treated. Further studies should focus on sex-based differences in innate and adaptive immune system and their association with BCG response.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00345-021-03653-1.

Natural Killer Anti-Tumor Activity Can Be Achieved by In Vitro Incubation With Heat-Killed BCG

Natural Killer cell receptors allow this heterogeneous immune population to efficiently fight both tumors and infection, so their use as immunotherapy agents is an active field of research. Cytokine activation, particularly by myeloid cell-derived IL15, can induce potent NK anti-tumor responses. While studying the mechanism of action of intravesical instillations of Bacille Calmette-Guérin (BCG) as therapy for patients with high risk non-muscle invasive bladder cancer, we showed that BCG can activate a cytotoxic CD56^bright NK cell population which efficiently recognized bladder cancer cells. This pioneer immunotherapy provides an invaluable model to understand the role of different immune populations in tumor elimination. However, during the propagation of BCG worldwide a large number of genetically diverse BCG substrains developed. Here, we investigated the capacity of different BCG substrains to promote NK cell activation and confirmed that they were able to activate lymphocytes. Tice, Connaught and Moreau were the substrains with a stronger NK activation effect as measured by CD56 upregulation. Surprisingly, dead mycobacteria also stimulated PBMC cultures and we further demonstrate here that subcellular fractions of BCG-Tice, in the absence of live mycobacteria, could also induce an NK cell response. Lipids from BCG-Tice, but not from Mycobacterium bovis, stimulated NK cell activation and degranulation, whereas the aqueous fraction of either bacteria did not activate lymphocytes. However, delipidated BCG-Tice bacteria were able to activate effector cells (CD3⁺CD56⁺ and NK, CD3^-CD56⁺). These data demonstrate that different components of mycobacteria can stimulate different immune subpopulations resulting in phenotypes suitable for cancer elimination.

A severe complication of intravesical bacillus Calmette-Guerin: An effect of different strains

The use of intravesical BCG has improved the survival and outcomes in the treatment of bladder cancer. However, the worldwide shortage of OncoTice BCG has caused disruption and changes in treatment regimes, leading to use of alternative strains. We describe a severe complication as the result of using intravesical SII Onco BCG for the treatment bladder cancer, in an 82 year old man presenting with granulomatous epididymo-orchitis.

Assessment of the oncological outcomes of three different bacillus Calmette-Guérin strains in patients with high-grade T1 non-muscle-invasive bladder cancer

Objective

: To determine whether there are significant differences in oncological outcomes between three different bacillus Calmette–Guérin (BCG) strains used for adjuvant intravesical immunotherapy in patients with high-grade T1 (T1HG) non-muscle-invasive bladder cancer (NMIBC).

Patients and methods

: Data of 590 patients with a diagnosis of primary T1HG NMIBC were retrospectively reviewed. The study included 138 (23.4%) patients who were treated with the Moreau, 272 (46.1%) with the TICE, and 180 (30.5%) with the RIVM strains. All patients included in the analysis received at least five instillations of an induction course and at least two installations of a maintenance course. Due to existing differences in baseline patient characteristics, the association between oncological outcomes and strain groups was investigated by complementary analysis with the implementation of inverse probability weighting (IPW).

Results

: The 5-year recurrence-free survival (RFS) rate was 70.5%, 66.7% and 55.2% for the Moreau, TICE and RIVM groups, respectively (P = 0.016). The 5-year progression-free survival (PFS) rates were 84.4%, 85% and 77.8% in the Moreau, TICE and RIVM groups, respectively (P = 0.215). The IPW-adjusted Cox proportional hazard regression analysis did not show any differences in RFS between the Moreau and TICE groups (P = 0.69), whereas the RIVM strain was significantly associated with worse RFS compared to the Moreau (hazard ratio [HR] 1.69 for RIVM; P = 0.034) and TICE (HR 1.87 for RIVM; P = 0.002) strains. The IPW-adjusted analysis did not show any significant differences between study groups in terms of PFS.

Conclusions

: The results of the present study suggest that the Moreau and TICE strains might be superior to the RIVM strain in terms of RFS in patients with T1HG NMIBC.

Abbreviations: CIS: carcinoma in situ; IPW: inverse probability weighting; IQR: interquartile range; HR: hazard ratio; HG: high grade; LVI: lymphovascular invasion; MP: muscularis priopria; NMIBC: non-muscle-invasive bladder cancer; PFS: progression-free survival; RCT: randomised controlled trial; RFS: recurrence-free survival; T1HG, high-grade T1; (re-)TURB: (re-staging) transurethral resection of bladder; VH: variant histology