The Food and Drug Administration (FDA) has accepted the Biologics License Application (BLA) for VBI Vaccines’ 3-antigen prophylactic hepatitis B vaccine candidate for the prevention of infection caused by all known subtypes of the hepatitis B virus (HBV) in adults.

The vaccine candidate consists of the S, pre-S1, and pre-S2 surface antigens of the hepatitis B virus. The BLA is supported by data from 2 randomized, double-blind phase 3 studies, PROTECT (N=1607) and CONSTANT (N=2838), which compared the safety and immunogenicity of the vaccine candidate to Engerix-B® in patients 18 years of age and older.

Patients were randomly assigned to receive prophylactic hepatitis B vaccination with either 10µg of the vaccine candidate intramuscularly (IM) or Engerix-B IM on days 0, 28, and 168. 

In the PROTECT study, results showed that among the entire study population, a seroprotection rate (SPR) of 91.4% was observed in the vaccine candidate arm vs 76.5% for the Engerix-B arm (SPR difference: 14.9%; 95% CI, 11.2-18.6). In patients aged 45 years and older, SPR was 89.4% with the vaccine candidate compared with 73.1% with Engerix-B (SPR difference: 16.4%; 95% CI, 12.2-20.7).

In the CONSTANT study, the vaccine candidate demonstrated noninferiority with an SPR of 99.3% and 90.4% after 3 and 2 doses, respectively, compared with 94.8% and 51.6% for Engerix-B, respectively. Additionally, the vaccine candidate demonstrated lot-to-lot consistency.

“The FDA acceptance of our BLA represents a significant milestone for VBI, but more importantly for the effort to provide broad access to this vaccine, which we believe has the potential to be a meaningful intervention for adults in the fight against hepatitis B,” said Jeff Baxter, President & CEO.

A Prescription Drug User Fee Act (PDUFA) target date of November 30, 2021 has been set for this application.


  1. VBI vaccines announces U.S. FDA acceptance of BLA filing for VBI’s 3-antigen prophylactic hepatitis B vaccine. [press release]. Cambridge, MA: VBI Vaccines Inc.; February 2, 2021. 
  2. VBI vaccines announces second pivotal phase 3 study of Sci-B-Vac® meets primary and secondary endpoints. [press release]. Cambridge, MA: VBI Vaccines Inc.; January 9, 2020.