Thai Study Confirms Efficacy of Tenofovir (Viread) Regimens for HIV-HBV Coinfected Patients

By Liz Highleyman

Due to overlapping transmission routes, many people with HIV have also been exposed to hepatitis B virus (HBV). As the number of people infected with HIV increases in areas where HBV is endemic, such as southeast Asia, HIV-HBV coinfection is a growing concern that can complicate treatment for both disease.

Several approved and experimental anti-HBV drugs -- including tenofovir (Viread; also in the Truvada and Atripla coformulations), lamivudine (3TC; Epivir), emtricitabine (Emtriva), and, as recently reported, entecavir (Baraclude) -- are also active against HIV. Using such agents alone can lead to both viruses developing resistance.

Current HIV treatment guidelines recommend that HIV-HBV coinfected individuals who require therapy for chronic hepatitis B should receive a full HAART regimen containing dually active NRTIs.

As reported in the October 2008 issue of Hepatology, Gail Matthews and colleagues conducted a prospective clinical trial to compare anti-HBV monotherapy using lamivudine or tenofovir versus combination therapy with lamivudine plus tenofovir in HIV-HBV coinfected individuals in Thailand. A total of 36 coinfected patients initiating combination antiretroviral therapy for the first time were randomly assigned to receive either lamivudine, tenofovir, or both as anti-HBV agents within a HAART regimen.

Results

• At week 48, the median HBV DNA reductions from baseline were 4.07 log10 copies/mL in the lamivudine arm, 4.57 log10 copies/mL in the tenofovir arm, and 4.73 log10 copies/mL in the lamivudine + tenofovir arm (P = 0.70).

• In an intent-to-treat analysis, HBV DNA viral load was suppressed to < 3 log10 copies/mL in 46% of patients in the lamivudine arm, 92% in the tenofovir arm, and 91% in the lamivudine + tenofovir arm (P = 0.013).

• HBV resistant mutations were detected in 2 participants, both in the lamivudine arm.

• Hepatitis B "e" antigen (HBeAg) loss was observed in 33% of HBeAg positive patients and 8% experienced hepatitis B surface antigen (HBsAg) loss.

• Hepatic flares were observed in 25% of study participants.

Lamivudine monotherapy resulted in a greater proportion of subjects with HBV DNA > 3 log10 copies/mL at week 48 and in early resistance development, the study authors concluded.

"This study confirms current treatment guidelines that recommend a tenofovir-based regimen as the treatment of choice for HIV-HBV coinfection, but does not demonstrate any advantage of HBV combination therapy in this short-term setting," they wrote.

National Centre in HIV Epidemiology and Clinical Research, University of New South Wales, Sydney, Australia; HIV-Netherlands Australia Thailand Red Cross AIDS Research Centre, Bangkok, Thailand; Alfred Hospital, Melbourne, Australia; Department of Medicine, Monash University, Melbourne, Australia; Chulalongkorn University, Bangkok, Thailand; Victorian Infectious Diseases Service, Royal Melbourne Hospital, Melbourne, Australia; Victorian Infectious Diseases Reference Laboratory, Melbourne, Australia.

10/14/08

Reference
GV Matthews, A Avihingsanon, SR Lewin, and others. A randomized trial of combination hepatitis B therapy in HIV/HBV coinfected antiretroviral naive individuals in Thailand. Hepatology 48(4): 1062-1069. October 2008. (Abstract).