Abstract
There are two main bioengineering approaches to extending the half-life of factor
(F)VIII or FIX products used for hemophilia replacement therapy. These are fusion
to Fc-immunoglobulin G (FVIII and FIX) or to albumin (FIX) or pegylation/glycopegylation
(FVIII and FIX). Four FVIII and three FIX products are in clinical development or
have recently been licensed in regions of the world. The reported half-life extension
is approximately 1.5-fold for FVIII and 2.5-fold, or even longer, for FIX. Clinical
trials have shown promising results with respect to extension of dose intervals and
efficacy in the treatment and prevention of bleeding events. The role of these products
in clinical practice has been discussed in terms of either improving convenience and
adherence through prolongation of the interval between infusions or maintaining current
intervals thereby increasing trough levels and the safety margin against bleeds. This
review of extended half-life products addresses the possibilities and problems of
their introduction in hemophilia treatment.
Keywords
hemophilia A - hemophilia B - factor VIII - factor IX - prophylaxis