Concordance in assessments between investigators and blinded independent central review (BICR) in hematology oncology clinical trials: a meta-analysis

Background Blinded independent central review (BICR) mitigates assessment bias in oncology trials but imposes significant operational burdens. Its value in hematologic malignancies—where multimodal response criteria reduce reliance on subjective imaging assessments compared to solid tumors—remains unestablished. This meta-analysis evaluates BICR-investigator concordance specifically in hematology trials. Methods We systematically identified Phase II/III hematology trials (2014-2024) reporting progression-free survival (PFS) and/or objective response rate (ORR) assessments by both investigators and BICR from PubMed. Agreement was quantified using Pearson/Spearman correlation, pooled hazard ratio ratio (HRR, HRINV/HRBICR) for PFS, and odds ratio ratio for ORR (OddsRR, ORINV/ORBICR). We also analyzed the odds ratio for ORR for single arms (OddsINV/OddsBICR). Subgroup analyses assessed the impact of masking, cancer type based on imaging dependence, and sample size. Results Data from 70 studies (37 PFS comparisons; 23 ORR comparisons; 29 single-arm ORR) were analyzed. For PFS, the pooled HRR was 0.96 (95% CI: 0.89, 1.03), with perfect agreement in statistical significance (Cohen’s kappa = 1). For ORR, the pooled OddsRR was 0.99 (95% CI: 0.85, 1.14). Single-arm trials showed minimal odds difference between assessors (OR = 1.02, 95% CI: 0.90, 1.17). Subgroup analyses (masking, cancer type, sample size) consistently showed high agreement. Conclusions Investigator and BICR assessments demonstrated substantial concordance in hematology trials. The common applications of BICR in registration trials provide minimal added value for primary endpoint validation in this setting. We recommend prioritizing investigator training and standardized criteria to optimize resource allocation.