F8 and hemophilia: We thus treated adult immune tolerant hemophilia A mice (F8 knock out, KO, expressing a human mutated FVIII, R593C) (Bril et al, 2006) by i.v. delivery of the same dose of GP64-LV or VSV.G-LV expressing the codon-optimized human FVIII under the control of the F8 promoter (Merlin et al, 2019).