Recurrence-Free Survival (RFS) As a Surrogate Endpoint for Overall Survival (OS) in Adults with Early-Stage Hepatocellular Carcinoma (HCC): A Correlation Meta-Analysis of Randomized Controlled Trials (RCTS)
Leung L1, Singh P2, Ademisoye E3, Hofer K1, Qian A1, Kim I4
1Evidinno Outcomes Research Inc., Vancouver, BC, Canada, 2Bristol Myers Squibb, New York, NY, USA, 3Bristol Myers Squibb, Uxbridge, UK, 4Bristol Myers Squibb, Princeton, NJ, USA
OBJECTIVES: To evaluate RFS as a surrogate endpoint for OS in early-stage HCC by assessing treatment-level correlations using published literature.
METHODS: A systematic literature review was conducted by searching Embase, MEDLINE®, and CENTRAL from database inception to 07-20-2022 to obtain RCTs reporting HRs for RFS and OS for adults with early-stage HCC who had underwent curative ablation or resection. The correlation estimates between HRRFS and HROS were computed using bivariate random-effects meta-analysis (BRMA) and weighted linear regression (WLR) where trials were weighted by their sample size. Surrogacy equations were obtained from WLR. Validity of the surrogacy equations were assessed via leave-one-out cross-validation (LOOCV). Primary analysis included all trials (number of trials [n]=47). Several sensitivity analyses were conducted including (i) a sensitivity of trials that explicitly reported death in the definition of RFS (n=17) and (ii) a sensitivity of trials that explicitly reported death and were in the adjuvant setting (n=12).
RESULTS: In the primary analysis, the estimated correlation coefficient was 0.67 from BRMA (95% CI: 0.52, 0.79) and 0.73 (0.61, 0.85) from WLR. The resulting surrogate threshold effect was 0.77, suggesting that observing an HRRFS less than 0.77 is required to predict a nonzero positive effect on the HROS. The surrogacy equation was log(HROS)=‑0.12+0.97×log(HRRFS). In sensitivity analyses (i) and (ii), correlation estimates were even stronger (0.88 to 0.91). In LOOCV, alignment between observed and predicted HROS was 95.8% for the primary analysis and ranged from 91.7% to 96.2% for the sensitivity analyses.
CONCLUSIONS: Meaningful correlations between the treatment effects on RFS and OS in early stage were observed across all analyses. The highly accurate surrogacy equation between the treatment effects may enable earlier assessments of OS benefit from the RFS benefit for early-stage HCC. Restricting the evidence base to trials explicitly reporting death in the definition of RFS led to stronger correlation estimates.
Conference/Value in Health Info
Value in Health, Volume 26, Issue 6, S2 (June 2023)
Relating Intermediate to Long-term Outcomes