Name	Activity	Key findings
FDA-Approved Anti-HBV Agents
Lamivudine	Inhibits HIV reverse transcriptase and HBV DNA polymerase	Monotherapy (100 mg/day) associated with HBV DNA clearance or reduction in nearly all patients HBeAg seroconversion in only 17% at 1 year YMDD mutants are lamivudine-resistant, but probably replication-impaired Lamivudine withdrawal may result in severe hepatic flares
Interferon-alfa-2b	Antiviral and immunomodulatory effects	Compared with lamivudine, comparable clinical response rates and higher HBeAg seroconversion and HBsAg clearance rates Poor results in perinatally acquired disease and among Asian patients High rates of adverse effects Superior efficacy and reduced toxicity of pegylated forms of interferon
Investigational Anti-HBV Agents
Adefovir dipivoxil	Inhibits HIV reverse transcriptase (FDA approval was denied) and HBV DNA polymerase	Used at lower doses than were studied for HIV Produced -4.80 log10 copies/mL reduction in HBV DNA (9/35 patients undetectable) at week 72 among lamivudine-resistant patients 9% HBeAg seroconversion rate Well tolerated
Tenofovir disoproxil fumarate	Inhibits HIV reverse transcriptase (FDA-approved) and HBV DNA polymerase (investigational)	Active against HBV at doses used to treat HIV Produced -3.94 log10 copies/mL reduction in HBV DNA at 48 weeks among 12 lamivudine-resistant patients 1/12 HBeAg seroconversion
Emtricitabine	Inhibits HIV reverse transcriptase and HBV DNA polymerase (both investigational)	61% undetectable HBV DNA at 1 year at 200 mg/day, and 50% HBeAg seroconversion
L-dT	Inhibits HBV DNA polymerase only (investigational)	Up to 3.6 log10 copies/mL reduction in HBV DNA at 4 weeks among patients with wild-type HBV