HIV and Hepatitis.com Coverage of the
14th Annual Conference on Retroviruses
and Opportunistic Infections (14th CROI)
February 25 - 28, 2007, Los Angeles, CA

Hepatitis B Virus Kinetics and Treatment Response in HIV-HBV Coinfected Patients

Coinfection with HIV and hepatitis B virus (HBV) is associated with increased liver-related mortality and poorer response to anti-HBV treatment, but the kinetics of HBV decline during therapy in such patients is not well understood.

Among HIV negative, HBV monoinfected patients, there is a biphasic clearance of HBV following initiation of nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) active against the virus, similar to that seen following treatment of HIV and hepatitis C virus (HCV).

As reported at the 14th Conference on Retroviruses and Opportunistic Infections last month in Los Angeles, researchers conducted a viral kinetics sub-study of 18 patients enrolled in the Tenofovir in HIV/HBV Coinfection study (TICO). The study was conducted in Thailand, were HBV infection is highly prevalent.

In the TICO study, antiretroviral-naive participants were randomly assigned to receive one of the following 3 NRTI backbones as part of an efavirenz (Sustiva)-based HAART regimen:

• tenofovir (Viread) + AZT (Retrovir);
• lamivudine (3TC; Epivir) + AZT;
• tenofovir + lamivudine.

HBV viral load was measured throughout the 8-week study using a combination of the bDNA assay (limit of detection 2000 copies/mL) and the COBAS Taqman assay (limit of detection 200 copies/mL). HIV viral load, CD4 cell count, and alanine aminotransferase (ALT) were also quantified regularly.

Results

• All but 1 patient (17 of 18) experienced a biphasic decline in HBV viral load after starting treatment.

• Overall, the median HBV treatment efficacy was 98%, the median HBV virion half-life was 1.2 days, and the median infected cell half-life was 8.1 days.

• These parameters did not differ significantly from those previously observed in HBV monoinfected individuals using NRTIs active against HBV.

• There were no observed differences in HBV dynamic parameters among the 3 treatment arms.

• There was also no significant association between HBV dynamic parameters and CD4 cell count, HIV viral load, or ALT level.

Conclusion

"HBV viral kinetics following initiation of HBV-active HAART is not changed by HIV coinfection," the researchers concluded. "The efficacy of anti-HBV treatment (as measured by the inhibition of HBV production) in HIV-HBV coinfection is similar to that seen following treatment of HBV monoinfection."

Alfred Hosp, Melbourne, Australia; Monash Univ, Melbourne, Australia; Los Alamos Natl Lab, NM; HIV Netherlands Australia Thailand (HIV-NAT) Res Collaboration, Thai Red Cross AIDS Res Ctr, Bangkok; Chulalongkorn Univ, Bangkok, Thailand; Victorian Infectious Diseases Reference Lab, Melbourne, Australia; Natl Ctr for HIV Epidemiology and Clin Res, Sydney, Australia.

Link to study abstract

03/30/07

References
S Lewin, R Ribeiro, A Avihingsanon, and others. Hepatitis B Virus Kinetics Is Similar in HIV/HBV-co-infected and HBV-mono-infected Individuals. 14th Conference on Retroviruses and Opportunistic Infections; February 25-28, 2007; Los Angeles, California. Abstract 949 (poster).

 











































14th croi