Tenofovir (Viread) provides an effective long-term treatment for hepatitis B as a component of antiretroviral therapy in HIV-positive individuals, according to two studies presented to last week's Third International Workshop on HIV and Hepatitis Coinfection in Paris. The studies were conducted in London and Duesseldorf. The investigators from London also told the workshop that tenofovir had provided a potent anti-hepatitis B therapy even in patients who had 3TC (lamivudine, Epivir -resistant hepatitis B.
Investigators from London’s Chelsea and Westminster Hospital, which is the largest HIV treatment centre in Europe with recognised expertise in treating HIV and hepatitis coinfection, presented data on 39 patients coinfected with HIV and hepatitis B who received tenofovir. The drug is not formally licensed for the treatment of hepatitis B in the UK, but the investigators used the drug off-label to treat coinfected individuals.
The patients had a median age of 47 years, 38 were male, and the median duration of tenofovir treatment was a little under five years (58 months).
3TC had been used to treat 30 of these patients for a median of 70 months and 56% of these individuals had developed 3TC-resistant hepatitis B, with most resistance located in the YMDD region.
Before tenofovir therapy was commenced, the patients had a median CD4 cell count of 318 cells/mm3 and 54% had an HIV viral load below 50 copies/ml. Liver function tests at baseline were generally abnormal, with median ALT levels being 61 IU/l . Only 13% of individuals had a normal ALT result, defined as 13 IU/l or lower.
Median hepatitis B viral load was 68,000,000 GEq/ml at baseline. This fell to a median of only 500 GEq/ml after 58 months of tenofovir therapy, with 83% of patients having an undetectable hepatitis B viral load. Tenofovir treatment resulted in 46% of patients becoming e-antigen negative.
Adverse events related to tenofovir treatment led to the discontinuation of tenofovir treatment by four patients, three because of kidney problems with one patient stopping the drug because of osteoporosis. Two patient died during follow-up, but in neither case was mortality related to the use of tenofovir.
Evidence from Germany also points to long-term effectiveness of tenofovir
Further evidence showing the efficacy of tenofovir in coinfected patients came from Duesseldorf. Data on four years of tenofovir therapy in twelve patients were presented.
After four years of tenofovir treatment, all twelve patients achieved an undetectable hepatitis B viral load and 83% normalised ALT levels. None of the patients developed resistance to tenofovir.
The German investigators note that their small sample size was a limitation of their study, and investigators from the Chelsea and Westminster hospital called for large, prospective, randomised controlled trials to determine the safety and efficacy of long-term tenofovir therapy in HIV/hepatitis B coinfected patients.
Tan L et al. Long term treatment with tenofovir in an open label study of individuals co-infected with HIV and hepatitis B. Third International Workshop on HIV and Hepatitis Coinfection, abstract 41, Paris, 2007.
Mauss S et al. Long term suppression of HBV by tenofovir in HIV/HBV-coinfected patients. Third International Workshop on HIV and Hepatitis Coinfection, abstract 38, Paris, 2007.