Tenofovir Disoproxil Fumarate Alone Versus Its Combination With Emtricitabine for Treatment of Chronic Hepatitis B

This study will test whether the combination of two medications, tenofovir and emtricitabine, are safer and more effective for treating chronic hepatitis B than tenofovir alone. Chronic hepatitis B is a liver disease caused by infection with the hepatitis B virus. Several medications, including standard and pegylated interferon and the anti-viral drugs lamivudine, adefovir, entecavir and telbivudine, are currently used to treat the disease. Problems are associated with all of these agents, however, including development of viral resistance with long-term therapy of the anti-virals. Since many patients require long-term therapy to prevent their disease from worsening, a major goal of new approaches to treatment is to prevent the development of viral resistance. Combination treatment has been shown to be an effective strategy in preventing this resistance.

Tenofovir is an anti-viral drug approved for use in patients with HIV infection. In small studies in patients infected with both HIV and hepatitis B, tenofovir lowered the level of hepatitis B virus in the blood, with no viral resistance reported when used for up to 5 years. Emtricitabine is an anti-viral drug similar to lamivudine and is effective at lowering viral load and improving liver damage.

Patients 18 years of age and older with chronic hepatitis B may be eligible for this study. Participants are admitted to the NIH Clinical Center for a complete medical history and examination, including blood and urine tests, chest X-ray, electrocardiogram, abdominal ultrasound, Fibroscan (ultrasound exam of the liver that measures the amount of scarring), bone mineral density scan and liver biopsy. They are then randomly assigned to take combination treatment with tenofovir plus emtricitabine or tenofovir alone for at least 48 weeks. During the treatment period, patients visit the Clinical Center for blood tests and a physical examination every 2 weeks for the first month and then every 4 to 12 weeks. After 48 weeks, patients are readmitted to the Clinical Center for a complete evaluation that includes all the tests done at the start of therapy, including a liver biopsy. Patients who seem to have improved with treatment may continue therapy for up to 192 weeks, when they are again admitted to the Clinical Center for a complete medical evaluation and liver biopsy. Patients whose condition has not improved after 48 weeks of treatment have their treatment changed or stopped and continue to have regular outpatient clinic visits for 24 more weeks.