Hemophilia B Gene Therapy with a High-Specific-Activity Factor IX Variant.

Background: The prevention of bleeding with adequately sustained levels of clotting factor, after a single therapeutic intervention and without the need for further medical intervention, represents an important goal in the treatment of hemophilia.

Methods: We infused a single-stranded adeno-associated viral (AAV) vector consisting of a bioengineered capsid, liver-specific promoter and factor IX Padua (factor IX-R338L) transgene at a dose of 5×10 vector genomes per kilogram of body weight in 10 men with hemophilia B who had factor IX coagulant activity of 2% or less of the normal value. Laboratory values, bleeding frequency, and consumption of factor IX concentrate were prospectively evaluated after vector infusion and were compared with baseline values.

Human CD59 incorporation into porcine endogenous retrovirus particles: implications for the use of transgenic pigs for xenotransplantation.

Transgenic pigs have been engineered to express human CD59 (hCD59) in order to suppress hyperacute rejection of xenotransplants in human recipients. In this study, porcine endogenous retrovirus (PERV) was produced in a porcine cell line expressing hCD59 in order to examine the effect of this complement control protein on PERV neutralization by human sera. hCD59 was found to be incorporated into PERV particles produced from engineered ST-IOWA cells.