15 January 2021 - - Results from a Phase 4 study biopharmaceutical company VBI Vaccines Inc's (NASDAQ: VBIV) prophylactic 3-antigen hepatitis B virus vaccine in younger adults were published in Vaccine, the company said.

The study was designed to evaluate the immunogenicity of VBI's 3-antigen HBV vaccine in support of the qualification of that batch as a new reference standard for vaccine release to the Israeli market, where VBI's vaccine is available as Sci-B-Vac.

Prior to market release in Israel, batches of VBI's vaccine are tested against a reference vaccine batch that has been assessed in a clinical trial.

According to the European Pharmacopeia, the reference batch should elicit, after the full course of vaccination, a seroprotection rate of at least 95% in young and healthy adult participants.

In this open-label, single-arm Phase 4 study in 91 healthy adults age 20-40 years, this objective was achieved two months after the second dose the SPR at month 3 was 98.8% [95% CI: 93.7%, 99.7%].

SPR is defined as the percent of participants who achieve antibody titers (anti-HBs titers) above the protective threshold of 10 mIU/mL.

Additional results from this Phase 4 study include:

By month 7, after receiving three doses, all enrolled participants were seroprotected

The majority of participants were high responders, defined as achievement of anti-HBs titers ≥ 100 mIU/mL high-responder SPR was 81.4% and 97.6% at month 3 (after 2 doses) and month 7 (after 3 doses), respectively

The geometric mean concentration of anti-HBs titers were also substantially above the protective threshold at 413.6 mIU/mL and 6799.9 mIU/mL at month 3 and month 7, respectively

Anti-HBs titers were maintained above 2000 mIU/mL at month 12, suggesting a potent and sustained response

Consistent with other clinical data, VBI's 3-antigen HBV vaccine was well-tolerated with no safety signals observed

Participants in this study were immunized with 10 µg of VBI's HBV vaccine at months 0, 1, and 6.
The manuscript is available at: https: //www.sciencedirect.com/science/article/pii/S0264410X20316303.
About Hepatitis B

Hepatitis B is one of the world's most significant infectious disease threats with more than 290 m people infected globally.

HBV infection is the leading cause of liver disease and, with current treatments, it is very difficult to cure, with many patients going on to develop liver cancers.

An estimated 780,000 people die each year from complications of chronic HBV such as liver decompensation and hepatocellular carcinoma.

This vaccine is the only 3-antigen hepatitis B vaccine, comprised of the S, pre-S1, and pre-S2 surface antigens of the hepatitis B virus, and is approved for use and commercially-available in Israel.

In December 2017, VBI initiated patient dosing in a global Phase 3 clinical program that consisted of two concurrent pivotal studies: PROTECT, a safety and immunogenicity study, and CONSTANT, a lot-to-lot consistency study.

Data from both the PROTECT study and the CONSTANT study, which were announced in June 2019 and January 2020, respectively, comprise the basis for the regulatory submissions in the US, Europe, and Canada.

This vaccine is sold under the name Sci-B-Vac in Israel.