Clinical Trial Info

Lot-to-lot Consistency of Sci-B-Vac™ in Adults

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The primary objective of the Phase 3 study is to verify that the manufacturing equivalence of Sci-B-Vac™ is consistent and to compare the immunogenicity and safety of a three-dose regimen of Sci-B-Vac™ to a three-dose regimen of Engerix-B® in adults.


The CONSTANT Phase 3 clinical study demonstrated the consistency of immune response as measured by the geometric mean concentration (GMC) of hepatitis B antibodies (anti-HBs titers) across three consecutively manufactured lots of vaccine. 

High anti-HBs titers: GMC of anti-HBs for Sci-B-Vac was more than 7.5x compared to Engerix-B after 2 vaccinations (day 168) and more than 3x after 3 vaccinations (day 196)

Rapid Onset of Seroprotection: After 2 vaccinations, Sci-B-Vac elicited a 90.4% seroprotection rate (SPR) compared to 51.6% with Engerix-B, increasing to 99.3% vs. 94.8% after the 3rd dose

Safety: No new or unexpected safety signals seen with either study vaccine