Clinical Trial Info

Immunogenicity and Safety of Sci-B-Vac® to Engerix-B® in Adults

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This Phase 3 study is a double-blind randomized controlled trial designed to establish the non-inferiority of Sci-B-Vac® compared to Engerix-B® in adults ≥ 18 years old and the superiority of Sci-B-Vac® compared to Engerix-B® in adults ≥ 45 years old. Study subjects are randomized 1:1 to receive either a total of 3 injections of Sci-B-Vac® or 3 injections of Engerix-B® intra-muscularly (IM) on Days 0, 28, and 168.

This study will have 1607 participants.


The results of this Phase 3 study are published in The Lancet Infectious Diseases.

The seroprotection rate (SPR) – defined as the percent of participants who achieved antibody (anti-HBs) titers above the protective threshold of 10 mIU/mL – in participants ≥ 18 years was 91.4% for VBI’s vaccine compared to 76.5% for Engerix-B at Day 196

The SPR in adults ≥ 45 years was 89.4% for VBI’s vaccine vs. 73.1% for Engerix-B at Day 196, exceeding the pre-set margins for statistical superiority and clinical superiority

In adults age 18-44 years, the SPR after two doses (Day 168) of VBI’s vaccine was comparable to three doses of Engerix-B (Day 196) – 87.2% vs. 91.1%, respectively

In all participants, the decrease of SPR from Day 196 (peak titers) to Day 336 (end of study) decreased less for VBI’s vaccine (91.4% to 89.0%) compared to Engerix-B (76.5% to 68.8%)

In all participants, VBI’s vaccine-elicited 6x higher Geometric Mean Concentration (GMC) of anti-HBs titers (1148.2 mIU/mL vs. 192.6 mIU/mL)

Regardless of age, BMI, or diabetic status, participants who received VBI’s vaccine had higher SPRs and 5-8x higher antibody GMC compared to Engerix-B

The safety and tolerability seen in this study were consistent with safety data from previous clinical studies – no safety signals observed in either vaccine arm, and no new safety.

Based on these results VBI will continue discussions with regulatory agencies in North America and Europe as they work to provide broad access to this vaccine candidate.