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Phase I, Multi-Centre, Randomised, Placebo-Controlled, Dose Escalation Study to Assess Local & Systemic Tolerability of Therapeutic DNA Plasmid pdpSC18 Vaccine Administered by Particle Mediated Epidermal Delivery Using PowderJect ND10 Delivery System in Subjects With Chronic Hepatitis B Infection

Hepatitis B virus (HBV) is responsible for the most common form of parenterally transmitted viral hepatitis. It is estimated that approximately 350 million people worldwide are persistent carriers of the virus and it is a major cause of acute and chronic infections of the liver, with significant associated morbidity and mortality. Chronic infection occurs in 98% of new-born children infected by vertical transmission from the mother and in 5% of individuals infected after 2 years of age. About 25% of these subjects will progress to cirrhosis and 20% of this subgroup will develop hepatocellular carcinoma - one of the most common cancers world wide. HBV is a non-cytopathic virus and liver injury is mainly mediated by the host immune response against virus-infected liver cells and by the production of inflammatory cytokines. A vigorous, polyclonal and multispecific cytotoxic and helper T cell response to HBV is readily detectable in the peripheral blood of subjects with acute self-limited hepatitis B, but is weak, antigenically restricted (mono- or oligospecific) or undetectable in subjects with chronic infection. A vigorous T cell response is thus believed to be responsible for the elimination of the hepatitis B virus. The aim of a therapeutic vaccine would be to enhance natural responses by boosting the appropriate cellular immune response to HBV. The purpose of this study is to evaluate the safety and tolerability profile of the pPDPSC18 DNA vaccine as administered by Particle Mediated Epidermal Delivery (PMED )