REP 2139-Ca + pegylated interferon + entecavir

This drug is a **combination therapy** consisting of **REP 2139-Ca** (a nucleic acid polymer serving as a hepatitis B surface antigen [HBsAg] release inhibitor), **pegylated interferon** (an immunomodulatory agent that boosts host immune response), and **entecavir** (a nucleoside analogue that inhibits hepatitis B virus [HBV] DNA polymerase). REP 2139-Ca works by blocking the assembly and secretion of HBV subviral particles, leading to rapid and substantial decline in circulating and intrahepatic HBsAg. This enhances immune-mediated clearance of HBV and hepatitis delta virus (HDV) co-infection, notably by allowing immunotherapies like interferon to be more effective[1][4][5][9]. Pegylated interferon acts by stimulating immune responses against viral infections. Entecavir is a direct antiviral targeting HBV DNA replication. The combination aims to provide synergistic antiviral effects against **chronic hepatitis B and hepatitis D coinfection**, offering deeper reductions in viral load, increased rates of HBsAg loss and seroconversion, and improved functional cure rates compared to monotherapy or dual regimens. Developed primarily by Replicor, this specific triple regimen is being studied in clinical trials for its safety, tolerability, and efficacy[4][1].