Hepatitis B in HIV patients: what is the current treatment and what are the challenges?

Chronic hepatitis B affects 5-10% of HIV patients in Western countries. Lamivudine should no longer be used as a single anti-HBV agent in HIV-HBV co-infected patients, given its limited antiviral potency and high risk of selection of resistance, which further results in wide cross-resistance to all other nucleoside analogues. Recent reports of transmission of lamivudine-resistant HBV in HIV patients are of especial concern, and large surveillance studies suggest that it may occur in up to 10% of new HBV infections in Western countries. Another worrisome aspect of the selection of lamivudine-resistant HBV is the potential for selection of vaccine escape mutants. Currently, tenofovir must be viewed as the drug of choice in HIV-HBV co-infected patients in whom antiretroviral therapy is advised. Its co-formulation with emtricitabine (Truvada) is particularly convenient for treating both HIV and HBV in co-infected individuals. While pegIFN-alpha monotherapy for 1 year may be considered for HIV-HBV coinfected individuals with good spontaneous HIV control (elevated CD4 cell count, low plasma HIV-RNA), and certain HBV features (genotype A, HBeAg+, low serum HBV-DNA and elevated ALT), it is clear that very few coinfected patients fulfill these criteria. In HBeAg-negative HIV patients, adefovir may be an option but the relatively low antiviral potency of this drug discourages its wide use. Given its potential anti-HIV activity, both entecavir and telbivudine must only be prescribed with antiretroviral agents. Lack of information about potential pharmacodynamic interactions between entecavir and abacavir (both are guanosine analogues) or between telbivudine and zidovudine or stavudine (all are thymidine analogues) further discourages their concomitant use. At this time, most experts agree that early introduction of anti-HBV active HAART is the best strategy for the treatment of chronic hepatitis B in HIV patients, and Truvada must be part of the triple regimen.