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Bacillus Calmette-Guérin (BCG) with or without immune checkpoint blockade in BCG-naïve high-risk non-muscle-invasive
Mohammed Amine Saâd1, Abdelkarim Antari1, Imad Taleb2
1Medical Oncology Department - Mohammed V Military Teaching Hospital, Rabat, Morocco; Faculty of Medicine and Pharmacy - Mohammed V University, Rabat, Morocco.
Adding immune checkpoint inhibitors (ICIs) to Bacillus Calmette-Guérin (BCG) maintenance therapy significantly improves event-free survival for high-risk non-muscle-invasive bladder cancer. However, induction-only therapy offers no benefit, and increased toxicity necessitates careful patient selection.
Area of Science:
- Oncology
- Immunotherapy
- Urologic Oncology
Background:
- Non-muscle-invasive bladder cancer (NMIBC) represents 75% of bladder cancer cases.
- Standard treatment (transurethral resection + BCG instillation) has a 30-40% relapse rate in high-risk patients.
- Novel therapeutic strategies are needed to improve outcomes in high-risk NMIBC.
Purpose of the Study:
- To evaluate the efficacy and safety of immune checkpoint inhibitors (ICIs) combined with Bacillus Calmette-Guérin (BCG) versus BCG alone in BCG-naïve high-risk NMIBC.
- To determine the impact of combination therapy on event-free survival (EFS) and overall survival.
- To assess safety profiles and conduct subgroup analyses.
Main Methods:
- Systematic review and reconstructed individual patient data (rIPD) meta-analysis of three Phase 3 randomized controlled trials (RCTs).
- Individual patient data reconstructed from Kaplan-Meier curves using the IPDfromKM method.
- Primary endpoint: EFS for ICI plus BCG induction and maintenance (I+M) vs. BCG I+M alone. Secondary endpoints: EFS for induction only, overall survival, safety, and subgroup analyses.
Main Results:
- Combined ICI + BCG I+M significantly improved EFS compared to BCG alone (HR 0.77; p=0.006).
- ICI plus BCG induction only showed no significant benefit (HR 1.03; p=0.754).
- Grade ≥3 adverse events were more frequent with combination therapy (24.5% vs. 6.1%).
Conclusions:
- Combination therapy with ICI and full BCG maintenance significantly enhances EFS in BCG-naïve high-risk NMIBC.
- The benefit is dependent on BCG maintenance; induction-only BCG is not synergistic.
- Increased toxicity necessitates careful patient selection and biomarker-stratified validation for broader adoption.
