Joint WFH-ISTH session: issues in clinical trial design.

Haemophilia therapy is experiencing an unprecedented expansion in the number and novelty of clotting factor concentrates. Every product must be licensed by regulatory authorities, primarily on the basis of its safety and efficacy profiles. The low prevalence of haemophilia, and other inherited bleeding disorders, presents a significant challenge to patient recruitment for preauthorization clinical trials, especially given the low frequency of inhibitory antibodies, the major adverse event related to clotting factor exposure. Other challenges include a lack of harmonization between the major regulatory authorities in certain key areas, the selection of laboratory monitoring methodologies and the difficulty in obtaining high-quality phase IV safety data following authorization. These aspects will be reviewed in this session, which will also highlight the roles played by the World Federation of Hemophilia and International Society on Thrombosis and Haemostasis in the promotion of these discussions.