As reported at the 4th International AIDS Society Conference on HIV Treatment, Pathogenesis and Prevention last week in Sydney, Australia, researchers conducted a randomized study of HAART regimens containing tenofovir (Viread) or lamivudine (3TC, Epivir) in individuals coinfected with HIV and hepatitis B virus (HBV). Lamivudine and tenofovir are active against both HIV and HBV.

The TICO study included 36 antiretroviral-naive HIV/HBV coinfected patients in Thailand who were randomized (1:1:1) to received efavirenz (Sustiva)-based regimens containing lamivudine, tenofovir, or lamivudine + tenofovir. The mean age was 36 years and about one-third were women. The median CD4 cell count was very low, at about 36 cells/mm3. Most had HBV genotype C (83%) and were HBeAg positive (61%) at baseline; 3 had pre-existing liver cirrhosis.

Results

• In an intention-to-treat analysis at week 48, median HBV DNA reductions were similar in all 3 arms, between 4-5 logs.

• Percentages achieving HBV DNA below 200 copies/mL were:

- lamivudine: 46%;
- tenofovir: 75%;
- lamivudine + tenofovir: 64%.

• Percentages who still had HBV DNA above 1000 copies/mL were:

- lamivudine: 38%;
- tenofovir: 17%;
- lamivudine + tenofovir: 0%.

• 8% of patients in both the lamivudine and tenofovir arms experienced HBeAg seroconversion, compared with 18% in the lamivudine + tenofovir arm.

• Similar percentages experienced HBsAg loss (8%, 8%, and 9%, respectively).

• ALT normalization was also similar (31%, 42%, and 36%, respectively).

• 9 patients (25%) experienced hepatic flares, 4 of whom experienced HBeAg loss and 2 of whom experienced HBsAg seroconversion.

• 1 individual who experienced a flare died from hepatic decompensation.

• HBV drug resistance (mutations L180M + M204V) was observed in only 1 patient in the lamivudine group.

Conclusion

The researchers concluded that detectable HBV viremia greater than 1000 copies/mL at 48 weeks is a risk factor for the development of HBV drug resistance.

While these data suggest that combination therapy may be superior to lamivudine or tenofovir alone, further data are needed to confirm these results.

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

07/31/07

Reference
G Matthews, A Avihingsanon, S Lewin, and others. A randomized study of tenofovir (TDF) containing HAART compared to lamivudine (LAM) containing HAART in antiretroviral (ARV) naïve HIV/HBV coinfected patients in Thailand: 48 week findings. 4th International AIDS Society Conference on HIV Pathogenesis, Treatment and Prevention. Sydney, Australia, July 22-25, 2007. Abstract TUAB205.

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