VBI Looking To Market More Potent, Less Expensive Hepatitis B Vaccine

Sci-B-Vac was shown more effective at fewer doses than Engerix-B in a Phase III study. VBI Vaccines sees its hepatitis B vaccine hitting potential markets by 2021.

VBI Vaccines Inc. is hoping that the price point for its new hepatitis B vaccine, Sci-B-Vac, as well as a favorable outcome against GlaxoSmithKline PLC’s Engerix-B, will give the trivalent vaccine a leg up in the market. Sci-B-Vac showed non-inferiority overall, and superiority in key subgroups, in its first Phase III trial.

The company hopes to make its new hepatitis B vaccine, a standard protocol for medical personnel and their patients, among others. “The number one determinant of adoption is cost,” VBI CEO Jeff Baxter told Scrip. While the average price of hepatitis B vaccines is $42 per dose, VBI anticipates that it will price Sci-B-Vac at $60 per dose. However, that price essentially is on par, as Sci-B-Vac requires only two doses instead of three.

“It’s twice as effective at half the dose, so that means that … you can get twice as many people working twice as fast, with less vaccine,” he said.

PROTECT, the first of two Phase III studies of Sci-B-Vac, randomized 1,607 patients age 18 and older to Sci-B-Vac or Engerix-B. There were two groups of participants, each representative of potential consumers, Baxter explained.

“There’s the otherwise healthy 18- to 44-year-olds who need to be protected from hepatitis B because they are at high risk, due to their lifestyle, their travel or their jobs,” he said. “The infection rate among health care workers is very high, and there’s a very potent market among service-sector workers and the military, whose jobs require them to be vaccinated in order to interact with the public. And then there is the case of those at high risk because of their lifestyle – the I.V. drugs users, the ones who use opioids.”

The second group are patients 45 and older with co-morbidities including hypertension, diabetes, BMI over 30, chronic liver disease with renal failure, COPD and other conditions. Baxter said the co-morbidity data could make the drug more attractive to clinicians treating patients with chronic conditions. “For those that are metabolically challenged, those that are obese, smokers, people who drink heavily, safety is critical,” Baxter said. “Particularly with those co-morbidities, a clinician has to be confident in the safety of the product.”

Sci-B-Vac successfully met both its co-primary endpoints in the PROTECT study, which was announced at IDWeek in October. In comparison to Engerix-B, Sci-B-Vac showed non-inferiority in seroprotection rates in all subjects age 18 and older. In subjects age 45 and older, Sci-B-Vac showed superiority of seroprotection rate compared to Engerix-B. Data presented at the American Association for the Study of Liver Diseases annual meeting 11 November in Boston showed that Sci-B-Vac had a rapid increase in anti-hepatitis B surface antigen (HBsAg) titers and rapid seroprotection compared to Engerix-B.

Antibody geometric mean concentration (GMC) was five to eight times higher in subjects who received Sci-B-Vac compared to Engerix-B, regardless of age, body mass index, diabetic status, and gender, according to the AASLD poster. And at all time points, subjects receiving Sci-B-Vac also showed a more rapid increase in anti-HBsAg titers, with higher seroprotection rates, than subjects who received Engerix-B, suggesting a more rapid onset of protection.

Protection that kicks in sooner and at fewer doses, said Baxter, will make Sci-B-Vac less costly than other hepatitis B vaccines, despite a higher price per dose. “In the 18-44s, we anticipate that patients will receive two doses of Sci-B-Vac versus three of Engerix B,” he said.

VBI chief medical officer Francisco Diaz-Mitoma told Scrip that Sci-B-Vac’s chief advantage is its formulation. “It’s a trivalent vaccine,” Diaz-Mitoma added, whereas other hepatitis B vaccines are monovalent, “and it’s formulated with an adjuvant that is of very common use in pediatric vaccines, aluminum hydroxide, so this is very safe.”

The data presented at AASLD showed higher rates of injection-site pain, tenderness and myalgia per injection with Sci-B-Vac compared to Engerix-B, but the poster notes the adverse events were mostly mild-to-moderate in intensity.

VBI isn’t phased by these findings. “One would expect a more immunogenic vaccine to produce more antigenicity, a reaction like tenderness and pain at the site,” explained Diaz-Mitoma. “In terms of managing that reaction, the people would generally take acetaminophen or ibuprofen for the pain. And the antigenicity disappeared in about seven days.”

VBI will file for regulatory approval after completing its next Phase III study, CONSTANT, which it expects to read out in 2020. The global trial is enrolling 2,900 patients 18-45 years of age, who are randomized to one of four vaccine courses. Three of the courses will consist of Sci-B-Vac doses from three different lots, while the control course consists of Engerix-B. The primary objective is demonstrating lot-to-lot consistency for immune response (measured by antibody GMC four weeks after the third vaccination; the secondary objective will be to evaluate safety and efficacy of Sci-B-Vac vs. Engerix-B.

Sci-B-Vac has been available in Israel since the 1980s. Development of the vaccine in the US and Canada stalled as halted studies changed hands several times in the midst of buyouts and mergers.

VBI expects regulatory approval in US and Canada by 2021.