Liver Biopsy Following Gene Therapy For Hemophilia

This observational study will obtain liver biopsy samples and evaluate the long-term effect of adeno-associated virus (AAV)-mediated gene therapy on the liver tissue in adult patients with hemophilia A or hemophilia B who have previously been treated with a factor VIII or factor IX gene-containing AAV-vector for liver-targeted gene transfer. Participants are from a cohort of patients treated with AAV-mediated gene transfer and at least 6 months after vector infusion.

This is a prospective cohort study evaluating the effect of AAV-mediated gene therapy on the liver in adult patients with hemophilia A or hemophilia B who have previously been treated with a FVIII/FIX gene-containing AAV-vector for liver-targeted gene transfer. To better understand the effect of AAV-mediated gene transfer on the liver, eligible participants can allow the use and analysis of already existing liver tissue samples, taken and preserved after having received gene therapy. Alternatively, eligible participants can consent to providing a new liver tissue sample which will be obtained by undergoing a standard transjugular liver biopsy (TJLB) procedure under moderate sedation. . The procedure will be done as outpatient (day 1) with post procedure follow-up on day 2, 3, 4 and 14.