Gene therapy for haemophilia: the end of a 'royal pathology' in the third millennium?

Haemophilia is an ideal condition for gene therapy because of its monogenet ic character and the fact that it requires only a small amount of the expre ssed protein to achieve palliation. To date, research in the field of gene therapy for haemophilia has largely relied on retroviruses, adenoviruses an d adeno-associated viruses as transfer vectors and the major aims will be t o achieve stable longlasting in vivo expression of factors VIII or IX (FVII I or FIX) at therapeutic levels. Two clinical trials have been approved by the US Food and Drug Administration (FDA), using miniadenovirus FVIII and t he intrahepatic and intramuscular delivery of adeno-associated virus FIX. I n the third millennium, haemophilia treatment should encompass more ambitio us goals through gene replacement, to result in permanent and safe haemophi lia 'eradication', making haemophilia a part of the history of medicine.