Dose-Escalation Study Of A Self Complementary Adeno-Associated Viral Vector For Gene Transfer in Hemophilia B

Inclusion Criteria: * Males ≥ 18 years of age with established severe HB (FIX:C\<1u/dl), * Treated/exposed to FIX products (e.g., concentrates or fresh frozen plasma) for at least 10 years or 50 exposure days. * A minimum of an average of 3 bleeding episodes per year requiring FIX infusions or prophylactic FIX infusions because of frequent prior bleeding episodes * Able to give informed consent and comply with requirements of the trial * Currently free of inhibitor and have no history of inhibitors to FIX protein * A negative family history for the development of an inhibitor, * Willing to practice a reliable barrier method of contraception until 3 sequential samples are negative for vector genomes using our PCR assay. Exclusion Criteria: * Evidence of active infection with Hepatitis B or C virus as reflected by HBsAg or NCV RNA positivity, respectively. To be considered negative for active infection, two negative assays at a minimum of a six month interval are required. * Exposure to Hepatitis B or C who are currently on antiviral therapy. * Serological evidence of HTLV or active HIV infection. Individuals who are effectively being treated with antiretroviral therapy are eligible. Specific criteria for effectiveness of treatment include the following: * Documented CD4+ T-cell count of \> 350 cells/mm\^3. * HIV-1 RNA viral load \< 400 copy/ml for at least the past 12 months, including at least 2 viral load test results of \< 400 copy/ml during the immediate 12 month i…