Sci-B-Vac-001 (PROTECT)

Trivalent hepatitis B (HepB) vaccine yields superior seroprotection rates in adults: results from the phase 3 double-blind, randomized study comparing immunogenicity and safety of a 3-dose regimen of Sci-B-Vac™ and Engerix B® (PROTECT)

Abstract of presentation given at IDWeek Washington DC, 4 October 2019

Timo Vesikari (Nordic Research Network, Tampere Finland) Joanne M. Langley, Bruce Smith, Pierre van Damme, Isabel Leroux-Roels, Geert Leroux-Roels, Johanna Spaans, Nathalie Machluf, Bebi Yassin-Rajkumar, David Anderson, Vlad Popovic, Francisco Diaz-Mitoma for the PROTECT Study Group


Many adults fail to achieve seroprotection after receiving 3 doses of monovalent S-antigen HepB vaccines such as Engerix-B® and the response decreases with age and with common co-morbidities. Sci-B-Vac™ is a trivalent HepB vaccine produced in mammalian cells, adjuvanted with aluminum hydroxide, which in addition to small S antigen, contains preS1 and preS2 antigens expressing highly immunogenic T and B cell epitopes that may enhance seroprotection rates (SPR) in adults.


The immunogenicity of 10 µg dose of Sci-B-Vac™ was compared with a 20 µg dose of Engerix-B® given at days 0, 28 and 168 (NCT03393754). Randomization of 1607 subjects was stratified by study center and age (18-44, 45-64, ≥ 65 years).


Seroprotection (anti-HBs level ≥ 10 mIU/ml) in Sci-B-Vac™ recipients age ≥ 18 years was 91.4% vs. 76.5% for Engerix-B®. Superiority analysis showed that SPR in Sci-B-Vac™ recipients age ≥ 45 years was 89.4% vs. 73.1% for Engerix-B®. These differences were statistically significant. Significantly higher SPR for Sci-B-Vac™ versus Engerix-B® was noted in subgroups (gender, BMI, diabetes, smoking and particularly age. No major safety signals were observed.


Sci-B-Vac™ was superior in adults aged ≥ 45 years, compared to the monovalent vaccine, Engerix-B®. Sci-B-Vac™ SPR was higher compared to Engerix-B® in key subgroups. No safety signals were observed. PreS1/preS2/S antigen containing Sci-B-Vac is a safe and effective vaccine to prevention of hepatitis B in adults.

Sci-B-Vac, hepatiitti B