VBI Vaccine’s Hepatitis B Vaccine Mostly Superior to GSK’s Engerix-B
The trial found that Sci-B-Vac was non-inferior to Engerix-B, two of its primary endpoints. Those endpoints were non-inferiority in all adults 18 years of age and older and superiority in adults 45 years of age or older.
However, the trial did not meet the secondary endpoint, non-inferiority in two doses of Sci-B-Vac at day 168 compared with three doses of Engerix-B at day 196.
“Hepatitis B is one of the most serious global infectious disease burdens, and successful vaccination of both adults and infants is critical to controlling and, hopefully someday, eradicating the disease,” stated Timo Vesikari, director of Vaccine Research Center at the University of Tampere Medical School in Finland. Vesikari is the principal investigator of the PROTECT and CONSTANT trials.
He went on to say, “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. 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.”
GSK’s Engerix-B was first approved in the U.S. in 1989. Hepatitis B is a viral disease that attacks the liver. It is spread via contact with blood or bodily fluids. According to the World Health Organization (WHO), 257 million people worldwide have hepatitis B.
In the trial, the seroprotection rate in patients 18 years and older who received Sci-B-Vac was 91.4% compared to 76.5% in patients who received Engerix-B. Seroprotection rate is a measure of how much clinical protection is provided.
The trial compared 10 micrograms of Sci-B-Vac against 20 micrograms of Engerix-B, and as reported, the Sci-B-Vac vaccine did a better job of offering protection against hepatitis B in all age groups compared to Engerix-B.
Sci-B-Vac has already been approved in Israel and 10 other countries. Although the age-group seroprotection data is significant, the failure of the secondary endpoints has investors concerned—shares dropped 58% at the news.
Data from the other late-stage trial, CONSTANT, which also compares Sci-B-Vac and Engerix-B, is expected by the end of the year.
“We remain on track to submit applications for regulatory approvals in the U.S., Europe, and Canada beginning mid-year 2020,” stated Jeff Baxter, VBI’s chief executive officer.
Of concern is yet another competitor, Dynavax and its Heplisav-B, which was approved in 2017. It has a better efficacy and convenience profile than Engerix-B, but was linked to a number of safety issues during its trial process.
The safety data on Sci-B-Vac in this new trial was consistent with what has been previously observed, with no new safety signals. Although Sci-B-Vac did not meet the secondary objective, the company noted that, “the SPR of Sci-B-Vac compared with Engerix-B was statistically significantly higher at each time point on a per-visit basis.”
The company expects to assess the non-inferiority of two doses of Sci-B-Vac compared to three doses of Engerix-B in both the CONSTANT study and an integrated data analysis from both PROTECT and CONSTANT.