Staged Phase I/II Hepatitis C Prophylactic Vaccine

A two stage, phase I/II, double-blinded, randomized, placebo-controlled study of hepatitis C virus (HCV)uninfected male and female injection drug users (IDU) aged 18 to 45. In this clinical trial AdCh3NSmut1 and MVA-NSMut HCV vaccine will be administered intramuscularly to 68 (+/-4) evaluable volunteers in stage 1. A planned interim analysis of safety and immunogenicity will be conducted based on data through 1 week after receipt of the second vaccination. If no safety signal is detected and there is evidence of a measurable immune response to HCV then an additional 472 (+/-4) volunteers will be enrolled in stage 2. The primary objectives of this study will be 1) to assess the safety of the new candidate hepatitis C virus vaccines, AdCh3NSmut1 and MVA-NSmut, compared to placebo when administered to HCV-uninfected injection drug users (IDUs) and 2) to determine if AdCh3NSmut1 and MVA-NSmut HCV vaccines will reduce incidence of chronic HCV infection compared to placebo among HCV-uninfected IDUs. The secondary objective of this study will be to evaluate the immunogenicity of the new candidate hepatitis C virus vaccines, AdCh3NSmut1 and MVA-NSmut, compared to placebo when administered to HCV-uninfected IDUs.The planned duration of the study is approximately 63 months total including accrual time for subjects (assuming 31 months of screening/enrollments, plus 3 months of halted enrollment for the first interim analysis), 2 months vaccination, 18 months follow-up of each enrolled subject, and 9 months extended observation (monthly), from the time of infection, for subjects becoming viremic in the last month of follow-up.