Event-free survival and complete response rate as surrogate endpoints for overall survival in high-risk non-muscle-invasive bladder cancer: meta-analysis

Meta-analysis of ten trials investigated event-free survival (EFS) and complete response rate (CRR) as surrogate endpoints for overall survival (OS) in bacillus Calmette-Guérin (BCG)-naïve or –remote high-risk non-muscle-invasive bladder cancer (HR NMIBC. Strong correlations were observed between EFS and OS at trial level (R=0.85; R²=0.72) and at arm level (R=0.90; R²=0.82). Trial-level associations between CRR and OS were weaker (R²=0.36 for 3-month CRR; R²=0.30 for 6-month CRR). Sensitivity analyses confirmed robustness of the primary results. The authors conclude that in BCG-naïve or –remote HR NMIBC, EFS shows strong correlation with OS at trial and arm levels, supporting its potential as a surrogate endpoint.