Study shows tenofovir's promise as treatment for people with HIV/HBV coinfection

Michael Carter
Estimated reading time 2 minutes
This article is more than 22 years old.

A small US study has found that the anti-HIV drug tenofovir is also effective against hepatitis B which is resistant to current treatments in people coinfected with HIV and hepatitis B.

The study, conducted by investigators at Washington University in St Louis, Missouri, is published in the 15th December 2002 edition of the Journal of Infectious Diseases.

Six HIV-positive people with evidence of persistent hepatitis B replication despite prior treatment with the currently licensed anti-hepatitis B drugs, interferon-alpha and 3TC FTC, were recruited to the study. All the study participants were receiving HAART and none had been treated with tenofovir before.

Glossary

pilot study

Small-scale, preliminary study, conducted to evaluate feasibility, time, cost, adverse events, and improve upon the design of a future full-scale research project.

 

prospective study

A type of longitudinal study in which people join the study and information is then collected on them for several weeks, months or years. 

replication

The process of viral multiplication or reproduction. Viruses cannot replicate without the machinery and metabolism of cells (human cells, in the case of HIV), which is why viruses infect cells.

log

Short for logarithm, a scale of measurement often used when describing viral load. A one log change is a ten-fold change, such as from 100 to 10. A two-log change is a one hundred-fold change, such as from 1,000 to 10.

liver function test (LFT)

A test that measures the blood serum level of any of several enzymes (eg, AST and ALT) produced by the liver. An elevated liver function test result is a sign of possible liver damage.

At entry to the study all the participants had extremely high hepatitis B viral loads (7.95 log) and abnormal liver function tests. Average CD4 count was 264 cells/mm3 (range 0-910) and median HIV viral load was a little over 1,300 copies/mL (range undetectable to 184,000). Liver biopsies were conducted on five of the trial members which revealed that four had cirrhosis.

A once daily 300mg dose of tenofovir was added to existing HAART regimens, with people in the study continuing to take 3TC or FTC. The trial lasted for 24 weeks and patients were seen at regular intervals for blood tests and physical examinations.

All six people completed the trial, with tenofovir showing only very mild disturbances to liver function. By week 12, average hepatitis B viral load had fallen to approximately 63,000 copies/mL, and by week 24 had fallen further to 4,000 copies/mL and was undetectable in two people (limit of detection 1,499 copiesm/L). The anti-hepatitis B response was found to be independent of the degree of immune suppression, with one patient with a CD4 count of zero achieving an undetectable hepatitis B viral load.

As expected tenofovir also showed anti-HIV activity, with HIV viral loads falling to an average of 265 copies/mL.

The investigators conclude that, “the results of this prospective pilot study are very promising and demonstrate the potent anti-HBV activity of TDF [tenofovir]in HIV coinfected individuals” adding that “tenofovir is a very promising drug for this indication and needs to be evaluated in the setting of prospective, randomized trials.” Such trials are currently recruiting at some London treatment centres, click here for details.

References

Ristig MB et al. Tenofovir disoproxil fumarate therapy for chronic hepatitis B in human immunodeficiency virus/hepatitis B virus – coinfected individuals for whom interferon-alpha and lamivudine therapy have failed. Journal of Infectious Diseases: 186, 1844-1847, 2002.

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