People with science or medical training can review the documentation in the Science section of our web site.
A more general description of hepatitis B can be found online on the World Health Organization website
Hepatitis B is a virus that infects the liver and, over time, damages the liver and affects its function. When considering the treatment of hepatitis B is it important to realize that most people that have been infected with the virus manage to clear the virus from their bodies. Their immune system detects the presence of the virus, and then attacks the virus to eliminate it. Of the estimated 2 billion people that have contracted hepatitis B over 80% have managed to clear the virus from their bodies. The other 20% that do not clear the virus from their bodies develop a chronic infection in the liver because their immune system becomes unable to control the virus. The challenge in restoring control of chronic infection is to restore the ability of the immune system to fight the HBV infection in the liver.
Replicor has made several important discoveries that will influence how chronic hepatitis B can be treated.
Replicor’s first discovery has been to demonstrate in patients that Replicor’s NAPs can reduce circulating surface antigen to undetectable levels over a 20 week treatment. NAPs target the assembly and release of subviral particles (SVPs) from infected liver cells. Almost all surface antigen (HBsAg) circulating in the blood comes from SVPs (for every infectious HBV virus there are more than 10,000 non-infectious SVPs). Circulating HBsAg interferes with the ability of the immune system to fight the virus and eventually overwhelms the patient’s immune response, allowing the infection to become chronic. For some patients the removal of HBsAg is enough to allow their immune system to completely suppress and establish control of their infection off treatment. This state is referred to as having a Sustained Virological Response (SVR).
The second discovery has been to understand the role of surface antigen. Replicor’s hypothesis, which has now been proven in four separate human clinical trials, is that by reducing and eliminating surface antigen with NAPs, the immune system is allowed to recover and regain control of the infection. More importantly, in those patients where removing HBsAg was not enough to restore immune control, the elimination of HBsAg greatly improved their response to immunotherapy compared to patients receiving immunotherapy without the benefit of HBsAg removal. This combination treatment of NAP-based HBsAg removal and concomitant immunotherapy results in high rates of restoration of immune control over HBV infection off treatment.
Patients should appreciate that, while Replicor’s proof of concept clinical trials are promising, it will still be several years before any NAP-based treatment could be approved for the treatment of HBV or HBV / HDV infection.