A randomized prospective trial comparing Bacillus Calmette-Guérin (BCG) RIVM and Russian strains in non-muscle invasive bladder cancer: Efficacy and side effects.

BACKGROUND

Intravesical Bacillus Calmette-Guérin (BCG) therapy is widely used as an adjuvant treatment for non-muscle-invasive bladder cancer (NMIBC). However, the optimal BCG substrain remains undetermined. This study compares the efficacy and safety of the BCG RIVM and Russian substrains in NMIBC treatment.

OBJECTIVE

To evaluate recurrence-free survival (RFS), progression-free survival (PFS), and adverse event profiles between the 2 substrains.

METHODS

In this randomized prospective trial, 149 patients with intermediate-, high-, and very high-risk NMIBC were randomized to receive either BCG RIVM or BCG Russian following transurethral resection of bladder tumor (TURBT). Patients with inadequate BCG therapy, short follow-up, or exposure to multiple strains were excluded from the per-protocol analysis (n = 125). Kaplan-Meier analysis was used to evaluate survival outcomes in both the per-protocol and intention-to-treat (ITT) populations. Adverse events were also assessed.

RESULTS

Of 125 patients, 61 received BCG RIVM and 64 received BCG Russian. Recurrence occurred in 17 (27.9%) and 19 (29.7%) patients in the RIVM and Russian groups, respectively (P = 0.822). The 48-month RFS rates were 72.1% (CI: 60.9-83.2) and 70.3% (CI: 59.2-81.4). Progression occurred in 4 patients (6.6%) vs. 8 patients (12.5%) in the RIVM and Russian groups, respectively (P = 0.365). The 48-month PFS rates were 93.4% (CI: 87.2-99.6) and 87.5% (CI: 79.4-96.9). Kaplan-Meier curves for RFS and PFS indicated no significant difference between the 2 groups (log-rank P = 0.875 for RFS and 0.267 for PFS). Similar findings were observed in the ITT analysis (log-rank P = 0.791 for RFS and 0.419 for PFS). Adverse events were reported in 76% of patients, with no significant differences between the groups in terms of toxicity (P = 0.545).

CONCLUSIONS

BCG RIVM and Russian substrains demonstrated comparable efficacy and safety, supporting substrain selection based on availability and institutional preference.