May 2, 2013
Combo of 2 HIV Drugs Can Control Hep B
The HIV antiretrovirals Viread (tenofovir) and Emtriva (emtricitabine), which are typically combined as Truvada, can suppress the hepatitis B virus (HBV) in three-quarters of those with “immune-tolerant” infection, MedPage Today reports. Immune-tolerant infection refers to a stage of the disease during which treatment usually isn’t recommended, but which may represent an important window of opportunity for preventing both liver cancer and transmission of the virus.
Participants in a study had a 76 percent viral suppression rate after four years on Viread and Emtriva, which was a significantly greater rate than the 55 percent who achieved viral suppression by taking Viread by itself. However, only a few participants became “immune-active”—indicating they had the robust immune response needed to force the infection into an inactive chronic carrier state. Furthermore, those who terminated treatment experienced viral rebound. These preliminary findings, not yet published in a peer-reviewed journal, were presented in abstract form at the International Liver Congress, the 48th annual meeting of the European Association for the Study of the Liver (EASL) in Amsterdam.
The study included 126 people who had hep B and viral loads of at least 1.7 x 107 IU per mL or blood and, as is typical in the immune-tolerant phase, normal levels of alanine aminotransferase. They were randomly assigned to take either daily Viread and Emtriva or Viread and a placebo. Thirty-five out of the 64 participants (54 percent) taking Viread reached a viral load of less than 69 IU per mL, compared with 47 out of the 62 taking combination therapy (76 percent).
Just three people experienced anti-HBe seroconversion, indicative of entering an inactive chronic carrier state, and five experienced HBeAg loss without seroconversion. None of the patients lost the viral surface antigen (HBsAg), which is an indicator of infection, and none developed antibodies to the antigen.
Around half of those who discontinued therapy after the study experienced viral rebound to pre-study counts after 24 weeks.
Immune-tolerant HBV almost always occurs in people infected with HBV at birth and typically leads to immune-active HBV in adulthood. Hepatitis B treatment is usually reserved for people with immune-active HBV, as the medical establishment has long believed that a robust immune response is needed to help achieve undetectable viral loads after beginning antiviral therapy. These new results suggest that treatment with tenofovir and emtricitabine may be effective in the absence of a robust immune response. Additional long-term data are needed to determine if treatment during the immune-tolerant phase actually helps reduce the risk of liver cancer.
To read the MedPage Today story, click here.
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