Sustained expression of functional cFIX in naive hemophilia B dogs treated with AAV2/8 vectors. AAV2/8 LSP-cFIX-W was administrated as a single intraportal injection into the liver of 2 hemophilia B dogs at a dose of 5.25 × 10¹² GC/kg (G43, ▪; H12, ○). (A) WBCT; normal range is 8 to 12 minutes as indicated by the shaded area; before treatment, WBCTs for both dogs were more than 60 minutes. (B) aPTT; shaded area indicates the normal range, which is 24 to 32 seconds; before treatment, aPTTs for G43 and H12 were 101.9 seconds and 98.2 seconds, respectively. The reduction of aPTT after vector treatment in both dogs was significant (P ≤ .001, ANOVA). (C) Plasma cFIX antigen levels; dotted line represents the therapeutic level (250 ng/mL).