Efficacy and Safety of Sci B Vac vs. Engerix in Dialysis Patients

This is an open label clinical study designed to evaluate the safety and immunogenicity of Sci-B-Vac Hepatitis B Vaccine compared to Engerix-B Hepatitis B Vaccine in dialysis patients. The study hypothesis is that vaccination with Sci B Vac will achieve a higher seroprotection rate and a higher anti-Hepatitis B surface antibody serum titer level than vaccination with Engerix-B Dialysis patients will be categorized as "naïve" or "previously vaccinated" and each group will be randomized to treatment. Naïve patients randomized to Sci-B-Vac Hepatitis B vaccine will receive vaccination in three doses, 10 μg each, at 0, 1, and 6 months, or Engerix-B Hepatitis B vaccine given in four doses, 40 μg each, at 0, 1, 2, and 6 months. Previously vaccinated patients randomized to Sci-B-Vac Hepatitis B vaccine will receive vaccination in three doses, 20 μg each, at 0, 1, and 6 months, or Engerix-B Hepatitis B vaccine given in four doses, 40 μg each, at 0, 1, 2, and 6 months. All vaccines will be administered via intra-muscular injection to the deltoid muscle. The study will consist of three periods: a screening period of up to four weeks, a 24-week open-label treatment period, and a 24-week safety follow-up period. The total expected duration of the study per subject is 52 weeks as follows: Screening period: approximately 4 weeks; treatment period: 24 weeks; and follow up period: 24 weeks. The primary endpoint is the by-vaccine difference in the proportion of subjects attaining seroprotective immune response (anti-Hepatitis B surface antibody ≥ 10 IU/mL) 4 weeks after the last vaccination with either Sci-B-Vac or Engerix-B. Secondary endpoints include anti-Hepatitis B surface antibody geometric mean concentrations calculated for all subjects upon last active dose; the proportion of subjects with anti-Hepatitis B surface antibody concentrations equal to or above 10 IU/mL for all subjects at 12 weeks following the first vaccine dose; the by-treatment difference in serum titer levels of anti-Hepatitis B surface antibodies at 12, 24 and 52 weeks following the first vaccination. A by-vaccine comparison of adverse events will also be performed.