Ten second-line phase II trials with individual patient outcomes data evaluating chemotherapy or biologics were combined for discovery, followed by external validation in a phase III trial. The relationship between PFS6/RR and OS12 was assessed at the trial level using Pearson correlation and weighted linear regression, and at the individual level using Pearson chi-square test with Yates continuity correction.
In the discovery dataset, a significant correlation was observed between PFS6 and OS12 at the trial (R2聽= 0.55, Pearson correlation聽= 0.66) and individual levels (82%, 覛聽= 0.45). Response correlated with OS12 at the individual level less robustly (78%, 覛聽= 0.36), and the trial level association was not statistically significant (R2聽= 0.16, Pearson correlation聽= 0.37). The correlation of PFS6 (81%, 覛聽= 0.44) appeared stronger than the correlation of response (76%, 覛聽= 0.17) with OS12 in the external validation dataset.
PFS6 is strongly associated with OS12 and appears more optimal than RR to identify active second-line agents for advanced UC.