Amit Nathwani at the University College London Cancer Institute and his colleagues tested a gene therapy approach for hemophilia B using an adenovirus-associated virus vector — one that's different from previously used adenovirus vectors — to deliver a corrected coagulation factor IX, or FIX, gene. As they report in the New England Journal of Medicine, Nathwani and his team performed a combined phase 1 and 2 clinical trial of their approach on six male patients with hemophilia B. "We have found that a single peripheral-vein infusion of our scAAV2/8-LP1-hFIXco vector consistently leads to long-term expression of the FIX transgene at therapeutic levels, without acute or long-lasting toxicity in patients with severe hemophilia B," the authors write.
"The idea of treating hemophilia with gene therapy has been around for 25 years, but the problem was how to do it right," says Ronald Crystal from Weill Cornell Medical College in The Wall Street Journal. "This is an important breakthrough because it is the first success in one of the plasma deficiency disorders and shows gene therapy is feasible."