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.