A Bridging Study: Comparing Two Lots of Sci-B-Vac™ and Engerix-B in Healthy Adults

This was a single-blind, 3-arm, comparative, controlled, randomized, study conducted at one site in Vietnam whose primary objective was to demonstrate clinical equivalence of the two production lots of Sci-B-Vac vaccine produced at two different facilities (OLD facility (Lot A) and NEW facility (Lot B) with respect to anti-hepatitis B-Surface (HBs) response. Secondary efficacy analysis was performed to demonstrate non-inferiority of seroprotection of each lot of Sci-B-Vac vaccine when compared to Engerix-B vaccine

This was a single-blind, 3-arm, comparative, controlled, randomized, study conducted at one site in Vietnam. Following a screening period, healthy eligible subjects (n = 402) were enrolled and randomized to receive Sci-B-Vac (OLD facility (Lot A) and NEW facility (Lot B), or Engerix-B. The study was conducted in two stages, approximately a year-and-a-half apart. In the first stage (Stage I) beginning in March 2006, Sci-B-Vac (Lot A) vaccine was compared to Engerix-B; and in the second stage (Stage II) beginning in November 2007, the Sci-B-Vac (Lot B) vaccine was compared to Engerix-B. The subjects assigned to the Engerix-B group were equally divided between the stages, 67 subjects in the Engerix-B group in Stages I and II, respectively, for a total of 134 subjects, such that the final number of randomized subjects in Stage 1 and Stage 2 across the Sci-B-Vac Lot A, Sci-B-Vac Lot B and Engerix-B was 1:1:1, respectively. Immunogenicity evaluations for Stage I data (Visits 5 and 6) were conducted together with Stage II data.

Sci-B-Vac, Prophylactic vaccine, Hepatitis B vaccines, Phase 3, pre-S1, pre-S2, Surface antigen, 3-antigen

The 3-antigen HepB vaccine, Sci-B-Vac-SciGen (SciGen Israel Ltd., produced in a new production facility located in Rehovot, Israel) contains three recombinant proteins of hepatitis B virus (HBV) envelope: small S, medium pre-S2, and large pre-S1 surface antigens. Sci-B-Vac-SciGen was supplied in a final volume of 1.2 ml vials

The single antigen HepB vaccine, Engerix-B (GSK), contains the small S recombinant protein. Engerix-B was supplied in 1.0 ml vials.

The 3-antigen HepB vaccine, Sci-B-Vac-BTG (Bio-Technology General (BTG) Ltd., Rehovot, Israel.) contains three recombinant proteins of HBV viral envelope: small S, medium pre-S2, and large pre-S1 surface antigens. Sci-B-Vac-BTG was supplied in a final volume of 1.2 ml vials

Engerix-B (hepatitis B vaccine (recombinant)) is indicated for active immunization against hepatitis B virus infection

Percentage of Participants With an Antibody Response (≥10 IU/Liter) to Hepatitis B Surface Antigens One Month After the Third Vaccination

Percentage of participants with an antibody response to hepatitis B surface antigens (anti-HBs), defined as an anti-HBs titer ≥10 IU/liter, one month after the third vaccination (Day 210) in the According-to-Protocol (ATP) population.

Percentage of participants with an anti-HBs antibody response, defined as an anti-HBs titer ≥10 IU/liter, just prior to the third vaccination (Day 180) and 1 month (Day 210) and 6 months (Day 360) after the third vaccination in the According-to-Protocol (ATP) population.

Geometric mean concentration (GMC) of anti-HBs antibody just prior to the third vaccination (Day 180) and 1 month (Day 210) and 6 months (Day 360) after the third vaccination in the According-to-Protocol (ATP) population.

Percentage of participants with an anti-HBs antibody response, defined as an anti-HBs titer ≥100 IU/liter, just prior to the third vaccination (Day 180) and 1 month (Day 210) and 6 months (Day 360) after the third vaccination in the According-to-Protocol (ATP) population.

Inclusion Criteria: Healthy adults 18 to 45 years of age who were seronegative for HBsAg, anti-HBs, anti-Hepatitis B core antigen, HIV, and Hepatitis C Virus (HCV) Exclusion Criteria: Evidence of alcoholism or drug abuse, history of HIV, or HCV Blood transfusions within the three months prior to inclusion in the study Uncontrolled hypertension and other cardiovascular diseases Chronic/concurrent administration (>14 days) of immunosuppressants or other immune-modifying drugs within six months prior to the first vaccine dose. Inhaled and topical steroids were permitted History of anaphylaxis (including shock) or any significant allergy or atopy

Diaz-Mitoma F, Popovic V, Spaans JN. Assessment of immunogenicity and safety across two manufacturing lots of a 3-antigen hepatitis B vaccine, Sci-B-Vac(R), compared with Engerix-B(R) in healthy Asian adults: A phase 3 randomized clinical trial. Vaccine. 2021 Jun 29;39(29):3892-3899. doi: 10.1016/j.vaccine.2021.05.067. Epub 2021 Jun 8.