VBI Vaccines Inc. (NASDAQ: VBIV) recently announced a global Phase III clinical trial for its flagship vaccine, Sci-B-Vac. Approval could unlock billions of dollars in annual sales globally.
Sci-B-Vac is a third generation hepatitis B vaccine. There is an urgent need for a better hepatitis B vaccines, as most vaccines only target one (S) antigen. There are two additional antigens (pre-S1/S2) that are neglected by current, second generation vaccines. This is a problem, especially for elderly patients born before the existing vaccines were available. Elderly patients have a much lower response rate when administered second generation vaccines (40% vs. 90% for the young). Such patients may benefit immensely from the introduction of third generation vaccines.
Sci-B-Vac targets all three surface antigens of the hepatitis B virus. It has a rapid protection onset, works at lower doses than competing vaccines, and is completely free from neurotoxic compounds.
Sci-B-Vac is already approved for use in 15 countries abroad, including Israel, one of the world’s top medical research hubs. VBI Vaccines is aiming to increase Sci-B-Vac’s adoption worldwide by getting the product approved by the FDA, the European Medicines Agency (EMA), and Health Canada.
VBI’s Phase III clinical trials are part of this process. Through these tests, the company will produce hard data that can demonstrate Sci-B-Vac’s safety and efficacy compared to competing products. VBI’s phase III tests will have more than 4,800 participants.
A Global Clinical Trial
VBI has already proposed its Phase III clinical program to the FDA, EMA and Health Canada. The company is ready to embark on an ambitious run of more than 40 tests across the U.S., Europe, and Canada. According to CEO Jeff Baxter, “We consider the outcome of discussions with the FDA, EMA, and Health Canada to be extremely positive… Sci-B-Vac’s extensive safety and efficacy data package demonstrates safe and effective vaccination of approximately 2,000 subjects in past clinical trials.”
Initiating Phase III tests is a major milestone for VBI. Clinical trials typically proceed through four phases. The fourth stage of testing occurs after a product is in the marketplace and involves collecting information about how the population is responding to the drug. Phase III is actually the final phase of controlled testing before the product is marketed to the public. This means that the upcoming tests will have a major effect on whether Sci-B-Vac is approved by the FDA, EMA, and Health Canada.
VBI’s Phase III program is divided into two studies, each with a clinically significant focus. PROTECT will test Sci-B-Vac’s safety and efficacy, while CONSTANT will also test its immune response.
PROTECT: Safety and Efficacy Study
PROTECT is the first of the two studies. It has two primary objectives:
(1) To show the non-inferiority of seroprotection induced by Sci-B-Vac compared to Engerix-B four weeks after volunteers take the vaccine.
(2) To prove that Sci-B-Vac has a better seroprotection rate than Energix-B four weeks after the last vaccination.
To evaluate these claims, VBI has set up a double-blind, two-arm, randomized, controlled study: 1,600 adult volunteers aged 18 and older will be randomized to receive either a course of Sci-B-Vac or a three-dose course of the control vaccine, Engerix-B. Enrollment will be age-group dependent. In addition to the two objectives above, the study will pursue multiple secondary objectives, including the seroprotection speed, safety and tolerability of Sci-B-Vac compared to Engerix-B.
CONSTANT: Consistency Study
The second study in VBI’s phase III trials is CONSTANT. Like PROTECT, it is a double-blind, two-arm, randomized and controlled study. The research objective is different, however, and was judged to require a separate trial. In CONSTANT, researchers will be trying to determine “lot-to-lot consistency for immune response as measured by geometric mean concentration of antibodies across three independent, consecutive lots of Sci-B-Vac.”
CONSTANT will require 3,200 volunteers aged 18-45 years. As with PROTECT, Sci-B-Vac’s results will be tested against a control vaccine, Engerix-B. Researchers will use blood samples to determine the antibody concentrations in volunteers’ bodies. The secondary objective is to determine the safety and efficacy of Sci-B-Vac compared to Engerix-B.
A New Solution to an Old Problem
VBI Vaccines is developing Sci-B-Vac to prevent hepatitis B infection. Hepatitis B is a disease of the liver marked by symptoms like nausea, vomiting, body aches and fever. It can also increase risk factors for more serious diseases, like renal failure and liver cancer.
Hepatitis B is often forgotten because in developed countries it is so well treated from childhood vaccines. In truth, the disease remains a serious problem in less developed nations, and may even make a comeback in wealthy nations. A changing geopolitical climate is seeing more and more refugees coming to Europe in response to social unrest. Especially notable was the European refugee crisis of 2016, which saw one million new refugees come to the continent in just a few months.
Assuming these trends continue, the elderly could find themselves at risk for hepatitis B infection. Many countries sending refugees to Europe do not widely immunize children, as is standard in Europe and North America.
The obvious solution to the problem (simply vaccinate the immigrants) is unfortunately not viable. The current vaccine is supposed to be administered in infancy, and efficacy drops if the doses are administered too late. If somebody is vaccinated very late in life, their odds of actually becoming immunized could drop below 40%.
Healthcare professionals accepted this fact largely because hepatitis B was thought not to be a problem in the U.S. and Europe. Social and economic trends require a total rethinking of this assumption. Globally, the population is aging, and this trend is most pronounced in affluent countries. Due to their low receptiveness to treatment, the elderly population may be at risk of contracting hepatitis B. Should this risk materialize, affected individuals will be at risk of serious side effects, due to the fact that older people are more likely to have immune deficiencies.
Sci-B-Vac could be a major step forward in the fight to eradicate hepatitis B worldwide. The vaccine’s efficacy has already been indicated in a number of clinical trials. It is already approved for sale in Israel, a nation with an excellent track record in medical research. Phase III clinical trials are poised to shed light on any remaining questions, and to obtain the approvals VBI needs from the FDA and other leading health organizations to unlock potential billions of dollars in annual sales.