During the first study, nine men with severe hemophilia A were observed after undergoing gene therapy. These men were susceptible to bleeding in joints and soft tissue, and required regular blood clotting injections to get by.
The team altered their genes using an adeno-associated virus (AAV), a type not known to cause any disease. It’s often used in gene editing to deliver artificially engineered DNA strands into target cells.
Shortly after this single infusion, the patients produced far more factor VIII – an essential blood-clotting protein – than usual. Those that received the highest dose of the infusion had normal levels of factor VIII for up to 24 weeks, which meant that, for all intents and purposes, they didn’t have any symptoms of hemophilia A. Additionally, no adverse toxicity effects nor immune reactions were detected.
A remedy for type A was described by the editorial as being “the ultimate grail,” and one that “was not expected to be feasible soon.” Now, the grail may be within reaching distance.
The second study looked at hemophilia B, and was led by the Division of Hematology at The Children’s Hospital of Philadelphia.
This type focused on the gene associated with factor IX, which also plays a role in blood coagulation, and which those suffering from type B have defective versions of, or simply lack. Once again, after a single AAV injection, the 10 participants in this study showed sustained average concentrations of factor IX.
In both cases, the patients didn’t require conventional treatments for extended periods of time after their infusions.
Is this therapy safe in the long-term, and is it just as effective? How will a larger sample size react to the treatment? Only more research will tell, but for now, these studies represent nothing less than groundbreaking steps towards that elusive cure.