Progression-Free Survival Early Assessment Is a Robust Surrogate Endpoint of Overall Survival in Immunotherapy Trials of Hepatocellular Carcinoma.

In trials of systemic therapies for advanced HCC, the surrogate relationship of PFS with OS is highly variable depending on treatment class (ICI or MKI) and evaluation time-point. In ICI trials, Q1-PFS and 12-month PFS-RMST are robust surrogate endpoints for OS.