Currently there are about 350 million chronic HBV patients worldwide and 786,000 reported HBV-related deaths in 2010. The U.S. is the largest individual market with the highest absolute growth rate of HBV patients at around 15.4% through 2033. The primary goal of treating chronic hepatitis B is to suppress HBV replication and induce liver disease remission prior to the onset of cirrhosis and hepatocellular carcinoma, which are often the result of an HBV infection if not managed. Learn more about chronic hepatitis B >>
The limited efficacy of current antiviral treatments highlights the need for new therapeutic tools for treating chronic HBV. Currently, there are seven FDA-approved drugs for the treatment of chronic HBV, including interferon-alpha, pegylated interferon-alpha, lamivudine, entecavir, telbivudine, adefovir dipivoxil, and tenofovir disporoxil fumarate. No currently approved drug is completely effective at suppressing HBV replication permanently.
Lamivudine often results in resistance development, with a 20% chance after one year, and 70% chance after two years. Adefovir has a much lower rate of resistance development, but has a lower level of potency against HBV. Various combinations of treatment have respective advantages and disadvantages, with none being ideal. Nucleoside analog (“NA”) therapy has advantages over interferon therapy (“IFN”) including fewer side effects and easier administration. However, IFN therapy has the advantage of decreased frequency of resistance, and higher rates of HBeAg loss, but also disadvantages of high cost, limited patient response, and administration by injection with frequent side effects.
Tenofovir so far, in combination with other drugs such as entecavir, is seen as the primary option for treatment, given its low cost, efficacy, and barrier to resistance development. Tenofovir is still is not completely effective in achieving the goals of chronic HBV therapy, which are to reduce the amount of detectible virus in the bloodstream of 95-100% of patients with no emergence of resistance, and the eradication of viral replication in the liver.