Section Review: Biologicals & Immunologicals: Gene therapy for haemophilia

Recently, there has been significant progress on the development of a gene therapy protocol for the treatment of haemophilia. Expression of physiologic levels of both human factors VIII and IX has been achieved in animal models, and correction of the disease phenotype has been demonstrated in haemophilia B dogs. Various durations of clotting factor expression in vivo have been observed. Adenoviral vector-mediated expression of therapeutic levels of human factor IX has been sustained for at least ten months in mice. Although research achievements have been substantial, several obstacles impede progress toward clinical trials. Improvements in gene transfer vehicles and delivery methods are needed to ensure safe and efficacious gene therapy. Specific issues currently under investigation include the persistence of clotting factor expression, procedures which allow re-administration of therapy, and host immune responses to treatment.