According to a new study published by the Journal of Clinical Oncology, researchers have found that radiographic progression-free survival (rPFS) was highly consistent and associated with overall survival in a randomized trial of abiraterone in patients with metastatic castration-resistant prostate cancer (mCRPC).
Because progression-free survival in mCRPC studies has been inconsistently defined and poorly associated with overall survival, researchers sought to study a reproducible quantitative definition of rPFS to test for an association with overall survival.
Researchers defined rPFS as "≥ two new lesions on an 8-week bone scan plus two additional lesions on a confirmatory scan, ≥ two new confirmed lesions on any scan ≥ 12 weeks after random assignment, and/or progression in nodes or viscera on cross-sectional imaging, or death."
Results showed hazard ratios of 0.49 (95% CI: 0.41 - 0.60; P <0.001) and 0.53 (95% CI: 0.45 - 0.62; P < 0.001). The Spearman's correlation coefficient between rPFS and overall survival was 0.72.
The findings suggest that rPFS should be further developed as an intermediate endpoint in trials studying patients with mCRPC.
A reproducible quantitative definition of radiographic PFS (rPFS) was tested for association with a coprimary end point of OS in a randomized trial of abiraterone in patients with mCRPC. rPFS was highly consistent and highly associated with OS, providing initial prospective evidence on further developing rPFS as an intermediate end point in mCRPC trials.