All Bacillus Calmette-Guérin (BCG) Strains Are Equal, but Some BCG Strains Are More Equal Than Others

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.

Mechanisms of BCG immunotherapy and its outlook for bladder cancer

BCG immunotherapy is the gold-standard treatment for non-muscle-invasive bladder cancer at high risk of recurrence or progression. Preclinical and clinical studies have revealed that a robust inflammatory response to BCG involves several steps: attachment of BCG; internalization of BCG into resident immune cells, normal cells, and tumour urothelial cells; BCG-mediated induction of innate immunity, which is orchestrated by a cellular and cytokine milieu; and BCG-mediated initiation of tumour-specific immunity. As an added layer of complexity, variation between clinical BCG strains might influence development of tumour immunity. However, more than 40 years after the first use of BCG for bladder cancer, many questions regarding its mechanism of action remain unanswered. Clearly, a better understanding of the mechanisms underlying BCG-mediated tumour immunity could lead to improved efficacy, increased tolerance of treatment, and identification of novel immune-based therapies. Indeed, enthusiasm for bladder cancer immunotherapy, and the possibility of combining BCG with other therapies, is increasing owing to the availability of targeted immunotherapies, including checkpoint inhibitors. Understanding of the mechanism of action of BCG immunotherapy has advanced greatly, but many questions remain, and further basic and clinical research efforts are needed to develop new treatment strategies for patients with bladder cancer.

Intravesical immunotherapy in nonmuscle invasive bladder cancer

Introduction:

Nonmuscle invasive urothelial cell carcinoma is the most frequent malignancy of the urinary bladder. The high recurrence rate (up to 80%) and risk of progression (up to 30%) reflect the need for long-term follow-up and sometimes multiple interventions. To reduce the rate of recurrences and tumor progression, intravesical immunotherapy, especially the use of Bacille Calmette-Guerin (BCG), represents the gold standard adjuvant treatment of high-risk nonmuscle invasive bladder cancer (NMIBC). This article reviews the role of BCG therapy and several promising new immunotherapeutic approaches such as mycobacterium phlei cell wall-nucleic acid complex, interleukin-10 (IL-10) antibody, vaccine-based therapy, alpha-emitter therapy, and photodynamic therapy checkpoint inhibitors.

Methods:

A systematic literature review was performed using the terms (immunotherapy, NMIBC, BCG, and intravesical) using PubMed and Cochrane databases.

Results:

BCG represents the most common intravesical immunotherapeutic agent for the adjuvant treatment of high-risk NMIBC. Its use is associated with a significant reduction of recurrence and progression. Patients with NMIBC of intermediate and high-risk benefit the most from BCG therapy. To achieve maximal efficacy, an induction therapy followed by a maintenance schedule should be used. Full-dose BCG is recommended to obtain ideal antitumoral activity and there is no evidence of a reduction of side effects in patients treated with a reduced dose. There are multiple new approaches and agents in immunotherapy with potential and promising antineoplastic effects.

Conclusions:

The beneficial effect of BCG is well documented and established. To reduce the tumor specific mortality, it is essential to follow guideline-based treatment. In patients with BCG-failure, there are new promising alternatives other than BCG but BCG remains the gold standard at this stage.

The Moreau Strain of Bacillus Calmette-Guerin (BCG) for High-Risk Non-Muscle Invasive Bladder Cancer: An Alternative during Worldwide BCG Shortage?

BACKGROUND

Bacillus Calmette-Guerin (BCG) is the standard of care for adjuvant intravesical instillation therapy for intermediate- and high-risk non-muscle invasive bladder cancer (NMIBC) after complete transurethral resection. Increasing evidence suggests that there are marked differences in outcomes according to BCG substrains. BCG-Moreau was recently introduced to the European market to cover the issue of BCG shortage, but there are little data regarding the oncologic efficacy.

METHODS

We retrospectively analyzed 295 consecutive patients, who received adjuvant intravesical instillation therapy with BCG-Moreau for intermediate- and high-risk NMIBC between October 2007 and April 2013 at a single institution. The end points of this study were time to first recurrence and progression to muscle-invasive disease.

RESULTS

Median age was 66 years (interquartile range 59-74, mean 65.9 years). According to the EAU risk group, 76 patients presented with intermediate-risk and 219 patients with high-risk NMIBC. The 5-year recurrence-free survival and progression-free survival rate was 64.8% (95% CI 52.8-74.4) and 81.4% (95% CI 65.2-90.2), respectively.

CONCLUSIONS

BCG-Moreau is an effective substrain for adjuvant instillation therapies of NMIBC, and outcomes appear to be comparable to series using other substrains. During worldwide shortage of BCG-TICE, Connaught and RIVM, BCG-Moreau may serve as an equally effective alternative.