Dose-dependent PK profiles and correlation of rFIXFc activity and Ag in plasma. (A) Plasma FIX activity and (B) plasma rFIXFc Ag levels over time after a single intravenous infusion of 12.5 (n = 1), 25 (n = 1), 50 (n = 5), or 100 (n = 5) IU/kg rFIXFc. Results presented are group mean ± SEM. (C) Correlation between plasma rFIXFc activity and Ag levels in 12 subjects who received a single dose of 12.5-100 IU/kg rFIXFc. Samples were collected up to 336 hours after dosing.