BCG immunotherapy for bladder cancer--the effects of substrain differences

Efficacy of intravesical Bacillus Calmette-Guérin therapy against tumor immune escape in an orthotopic model of bladder cancer

The aim of this study was to evaluate the antitumor immune response of the Bacillus Calmette-Guérin (BCG) in an orthotopic bladder cancer model. The murine bladder cancer cell line MBT-2 was transurethrally implanted in the bladder of syngeneic female C3H/He mice. The animals were randomly divided into three treatment groups: Phosphate-buffered saline (PBS), low-dose BCG and high-dose BCG. The analyses of luciferin-stained tumor images 28 days after each treatment showed significant tumor growth inhibition in the high-dose group in comparison with that in the low-dose- or PBS-treated groups. In addition, the percentage of myeloid-derived suppressor cells in the high-dose group was significantly suppressed in comparison with that in the PBS and low-dose agent treatment groups. These findings are notable in terms of the clinical evaluations of this therapy for patients with bladder cancer. The outcomes of this study also provide important implications regarding antitumor immune responses in human cancer.

Oral bacillus Calmette-Guérin vaccine against tuberculosis: why not?

The bacillus Calmette-Guérin (BCG) vaccine is the only licensed vaccine for human use against tuberculosis (TB). Although controversy exists about its efficacy, the BCG vaccine is able to protect newborns and children against disseminated forms of TB, but fails to protect adults against active forms of TB. In the last few years, interest in the mucosal delivery route for the vaccine has been increasing owing to its increased capacity to induce protective immune responses both in the mucosal and the systemic immune compartments. Here, we show the importance of this route of vaccination in newly developed vaccines, especially for vaccines against TB.

Treatment efficacy and tolerability of intravesical bacillus Calmette-Guerin (BCG)-RIVM strain: induction and maintenance protocol in high grade and recurrent low grade non-muscle invasive bladder cancer (NMIBC)

Background

BCG-RIVM strain was used in many treatment protocols for non-muscle invasive bladder cancer only as induction courses. Cho et al. (Anticancer Res 2012) compared BCG-RIVM induction and 'standard' maintenance (Lamm et al., J Urol. 2000) to mitomycin C. They found no statistically significant differences regarding disease recurrence and progression. The purpose of our study was to determine the efficacy & tolerability of this specific BCG RIVM strain, using six-weekly, induction course and single monthly instillations as maintenance for one year, in high risk recurrent, multifocal low grade and multifocal high grade pTa/pT1, CIS transitional cell carcinoma of bladder.

Methods

From 2003 - 2012, BCG-naive patients treated with intravesical BCG-RIVM for high-risk multifocal NMIBC were identified. Transurethral resection of bladder tumor (TURBT) and re-staging TURBT within six weeks, was done for accurate staging and complete elimination of disease. A six-weekly induction course, started 2-3 weeks after the last TURBT, followed by monthly maintenance protocol for one year. Recurrence, progression, cystectomy free survivals, cancer specific and over-all survival were determined.

Results

Sixty evaluable patients - median age 63, median follow-up 3.98 years. Forty-two patients (70%) completed BCG-RIVM treatment as planned. BCG termination was necessary in 18 patients (30%). Recurrence occurred in 16 patients (26.7%) at a median follow-up of 24.2 months while progression occurred in five patients (8.3%) at a median follow-up of 33 months. Recurrence-free survival and progression-free survival rates were 73% and 92% respectively. Cystectomy was performed in seven patients (12%) with a cystectomy-free survival of 88%. There were no cancer specific deaths. Two patients died of other causes (3.3%). The overall survival rate was 97%.

Conclusions

Our study is the first to show the clinical efficacy and tolerability of BCG-RIVM strain in the management of high risk NMIBC when given in a schedule of six-weekly induction with monthly maintenance for one year. Our maintenance protocol, achieved equivalent recurrence-free, progression-free, disease specific survival and overall survival to the reported literature and the more intense three-years South West Oncology Group (SWOG) protocol.