F8 intein precise CodopN6 reconstitution

Liver gene therapy with adeno-associated viral (AAV) vectors is under clinical investigation for hemophilia A (HemA), the most common inherited X-linked bleeding disorder. Major limitations are the large size of the F8 transgene, which makes packaging in a single AAV vector a challenge, as well as the development of circulating anti-F8 antibodies which neutralize F8 activity. Taking advantage of split inteins-mediated protein trans-splicing, we divided the coding sequence of the large and highly secreted F8-N6 variant in two separate AAV split-inteins vectors whose co-administration to HemA mice results in F8 protein reconstitution and expression of therapeutic levels of F8 over time without anti-F8 antibodies development.