GeoVax has partnered with Georgia State University to try to pursue an elusive goal—the development of an effective therapeutic vaccine for hepatitis B virus (HBV) infections.
The treatment of chronic hepatitis B has improved dramatically in recent years thanks to new antiviral drugs, but efforts to develop a therapeutic vaccine have largely ended in disappointment. Recent casualties among therapeutic HBV vaccines include GlobeImmune's GI 13020/GS-4774 which failed a Phase II trial causing partner Gilead to terminate a license for the candidate last November.
A therapeutic vaccine could boost chances for a functional immunological cure of the disease that could do away with the current need for lifelong suppression of the virus using nucleoside analog drugs like Gilead's tenofovir and Bristol-Myers Squibb's entecavir and interferon.
Chasing that goal, GeoVax and Georgia State say they are working on developing several vaccine candidates. The biotech—also based in Georgia—will contribute its modified vaccinia Ankara virus technology platform, which can be used to stimulate virus-like particles (VLPs) against specific antigens in patients and is already being used in vaccines against Zika and other serious diseases.
The university will contribute VLP design and functional assays developed by professor of chemistry Dr. Ming Luo, with assistance from Peking University Shenzhen Graduate School in China. Luo's work has focused on teasing out the molecular mechanisms that come into play during immune responses to HBV.
"The combined technologies and already defined functional assays will serve to rapidly test this innovative concept," said GeoVax' chief scientific officer Farshad Guirakhoo.
Hepatitis B is spread through blood and body fluids, attacking the liver and resulting in an estimated 650,000 deaths each year—most of them in low- and middle-income countries, according to the World Health Organization (WHO).
In the U.S. there are somewhere between 700,000 and 1.4 million people infected with HBV, say the Centers for Disease Control and Prevention (CDC), with 20,000 new infections every year.
Other companies in pursuit of therapeutic HBV vaccines include Abivax, whose ABX203 candidate is in mid-stage clinical testing, and Inovio Pharma with INO 1800 in Phase I testing, although that program took a knock when former partner Roche handed rights back last August. Altimmune has its HepTcell immunotherapy in Phase I, while another candidate from Chinese firm Kangtai Biologicals Products is also reported to have reached the clinical testing stage.
Aside from therapeutic vaccines, hopes of achieving a functional cure in HBV could also be met by new drug classes, including encapsidation inhibitors, entry inhibitors and TLR7 agonists, which are in various stages of development.