Efficacy and tolerability of bacillus Calmette-Guérin strain Russia for the treatment of non-muscle-invasive bladder cancer: Analysis of a prospective registry.

INTRODUCTION: Little is known about the efficacy and tolerability of intravesical bacillus Calmette-Guérin (BCG) strain Russia for treatment of non-muscle-invasive bladder cancer (NMIBC) in a middle- European population.

METHODS: A prospective collection of outcomes of 101 BCG-naive patients with urothelial bladder carcinoma was carried out between January 2013 and October 2023 at the University Hospital Basel, Basel, Switzerland. Patients underwent BCG (ONCO-BCGSIIL, Serum Institute of India, Pune, India) induction and a maximum of three maintenance cycles within one year. Adverse events were classified according to the World Health Organization rating scale.

RESULTS: One-, three-, and five-year recurrence-free survival (RFS) was 75.9%, 65.6%, and 61.6%, respectively. Tumor recurrence was seen in 31.7% of patients. One-, three-, and five-year progression-free survival (PFS) was 100%, 93.4%, and 93.4%, respectively. Cystectomy rate was 8.9%, with progression to muscle-invasive disease seen in two patients. Adverse events occurred in 72.3% of patients, with adverse events >class II seen in 8.9%. No BCG-related deaths occurred. Early cessation due to side effects resulting in non-adequate BCG therapy was seen in 3% of patients during induction and in 1% during maintenance therapy.

CONCLUSIONS: BCG Russia was well-tolerated and resulted in comparable RFS and PFS to historical results of prospective clinical trials with other BCG strains. The use of BCG Russia for adjuvant treatment of papillary NMIBC and therapy of carcinoma in situ of the urinary bladder could help alleviate the BCG shortage.