In the same study, in which the drug potency of ReFacto AF and a full-length recombinant factor VIII (FLrFVIII) comparator, and the FVIII activity measured in patient plasma samples were all determined using the same one-stage clotting assay at a central laboratory, ReFacto AF was shown to be pharmacokinetically equivalent to FLrFVIII in 30 previously treated patients (≥ 12 years) using the standard bioequivalence approach.