REP 2139-Ca / Pegasys™ Combination Therapy in Hepatitis B / Hepatitis D Co-infection

REP 2139-Ca is nucleic acid polymer. Nucleic acid polymers have been previously shown to clear serum hepatitis B virus surface antigen (HBsAg) both preclinically (in duck HBV infected ducks) and in human patients and to act synergistically with immunotherapeutic agents such as pegylated interferon-alpha 2a or thymosin alpha-1 to restore host immunological control of HBV infection. HBsAg is an essential component of the hepatitis D virus (HDV), therefore the direct action of REP 2139-Ca in removing serum HBsAg and its synergistic effect with pegylated interferon-alpha 2a is expected to have a significant antiviral effect against HDV infection. This study will examine the safety and efficacy of REP 2139-Ca therapy when used in combination with pegylated interferon alpha-2a in patients with HBV / HDV co-infection. The primary hypothesis to be tested is that this combined dosing regimen is safe and well tolerated in patients with HBV / HDV co-infection which will be assessed by examining the number of patients with adverse events (including reported symptoms and laboratory abnormalities). The secondary hypothesis to be tested is that this combined dosing regimen will have an antiviral effect against HBV / HDV co-infection in these patients which will be assessed by examining the following outcomes: 1. The number of patients with reductions in serum HBsAg. 2. The number of patients with reductions in serum HDAg and HDV RNA 3. The number of patients that experience a sustained antiviral response after treatment is stopped (reductions in serum HBV DNA and HDV RNA). The secondary hypothesis to be tested is that this combination approach can have an effective