15. How do the hepatitis B therapies work?

The treatment of hepatitis B is certainly a subject of a lot of debate or discussion and a lot of success at the moment. Over the last several years, there’s been tremendous breakthroughs in the treatment of hepatitis B. Hepatitis B is a DNA virus and it gets insinuated into the DNA of the host liver or the patients liver. It is extremely hard, once it’s settled in, to get rid of hepatitis B. So eradication of the virus totally from the body is very difficult. But the breakthrough is in the concept of how to deal with this disease. We now understand that it’s really not necessary to get rid of the virus but rather if we can suppress the replication of the virus we can prevent a development of the sequela. There are increasingly good statistics that show that the natural history of the disease is related to the active replication of the virus so we were looking for drugs that would suppress the viral replication. You can measure the viral level in the blood in most people who are infected. Now, remember that the virus replicates in the liver so in order to get viral particles measurable in the blood, especially with our new sensitive methods you must have the virus replicating in the liver to such an extent that its replicating fast enough to kill off so many liver cells or so many viruses that they’re now spilling over into the blood. If the virus was replicating very slowly, it would just go along slowly in the liver and it would affect a couple of liver cells and they would die and some would regenerate and then they would affect some other liver cells, but you wouldn’t find it in the blood. But if the virus is replicating very quickly, you find that it gets spilled out into the blood. We’ve found that if we can suppress the replication of the virus in the blood, we can significantly reduce if not eradicate the progression of the disease and that’s been the objective of the therapies. Suppression of viral replication leads to less inflammation, less fibrosis, less scarring, and a lower incidence of liver cancer. Total viral suppression and/or eradication essentially can prevent these problems of the sequela of hepatitis B.