Results from a phase 3 trial evaluating the immunogenicity and safety of Sci-B-Vac showed that the trivalent hepatitis B vaccine was found to be noninferior to Engerix-B (hepatitis B vaccine; GlaxoSmithKline).

In the PROTECT study, patients ≥18 years of age (N=1607) were randomized to receive prophylactic hepatitis B vaccination with either Sci-B-Vac 10µg intramuscularly (IM) or Engerix-B IM on Days 0, 28, and 168. The primary endpoint of the study was seroprotection rate (SPR; defined as the percentage of patients achieving seroprotection, anti-HBsAg levels ≥10 mIU/mL) at Day 196 both in adults ≥18 years of age and those ≥ 45 years old (roughly 80% of the patient population).

Findings from the study showed that among the entire study population, an SPR of 91.4% was observed in the Sci-B-Vac group vs 76.5% for the Engerix-B arm (SPR difference: 14.9%; 95% CI [11.2%, 18.6%]). In patients ≥45 years old, SPR was 89.4% with Sci-B-Vac compared with 73.1% with Engerix-B (SPR difference: 16.4%; 95% CI [12.2%, 20.7%]).

In subgroup analyses, Sci-B-Vac was associated with statistically significantly higher SPR vs Engerix-B in patients with diabetes (83.3% vs 58.3%, respectively), as well as those with a body mass index >30 (89.2% vs 68.1%, respectively). However, the study did not meet a secondary endpoint of noninferiority of 2 doses of Sci-B-Vac (at Day 168) vs 3 doses of Engerix-B (at Day 196); this efficacy measure will be reassessed once data from the CONSTANT study (expected at the end of 2019) become available. With regard to safety, no new risks or safety signals were identified in either group.

“These results are truly exciting and demonstrate, in a large multicenter controlled trial, the impressive efficacy of Sci-B-Vac at a dose half that of other hepatitis B vaccines,” said Dr Timo Vesikari, MD, PhD, Director of Vaccine Research Center at the University of Tampere Medical School in Finland, and a principal investigator of the PROTECT and CONSTANT studies. “If approved, this vaccine could play an important role in the prevention of hepatitis B, addressing a significant unmet medical need in the adult population.”

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Sci-B-Vac is currently approved for use in 11 countries. “Pending successful completion of CONSTANT, we remain on track to submit applications for regulatory approvals in the US, Europe, and Canada beginning mid-year 2020,” said Jeff Baxter, VBI’s president and CEO.

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