Human factor IX falloff studies, before and after AVC3FIX5 administration. Twenty-five units per kilogram of Mononine (Centeon) were injected intravenously and human factor IX plasma antigen levels were determined by ELISA at the time points shown. Preadenovirus falloff values are represented with solid symbols and are the average of 4 pre-AVC3FIX falloff studies (±1 standard deviation) as described previously by Lozier et al.1 Postadenovirus falloff values are represented by open symbols and each value is the average of ELISA results in duplicate for 1 falloff study at day 80. (▪) Low-dose, pre-AVC3FIX5; (•) intermediate-dose, pre-AVC3FIX5; (▴) high-dose, pre-AVC3FIX5; (□) low-dose, post-AVC3FIX5; (○) intermediate-dose, post-AVC3FIX5; (▵) high-dose, post-AVC3FIX5.