Changing drug regime ineffective, AIDS conference told

There is no advantage to taking a costlier combination of four drugs when first diagnosed with HIV, compared with the standard three-drug regimen, a U.S. study has found.

Earlier research suggested using four drugs might help reduce the amount of virus in the blood more quickly to avoid resistance, said Dr. Roy Gulick of Weill Medical College of Cornell University in New York, who presented the findings Sunday at the opening of the 16th International AIDS Conference in Toronto.

From March 2001 to March 2005, Gulick's team randomly assigned 765 patients to one of the drug combinations.

The four-drug regimen added the HIV drug abacavir to the standard three: zidovudine, lamivudine and efavirenz.

Undetectable levels

About the same number of patients in both groups achieved undetectable levels of HIV in their blood — 88 per cent in the four-drug group and 85 per cent for those taking three.

"Adding abacavir as a fourth drug to the standard initial three-drug regimen did not change toxicity or adherence but provided no additional benefit," the researchers concluded in the Aug. 16 issue of JAMA, a theme issue on HIV/AIDS published to coincide with the conference.

Patient advocates said adding a drug would increase the cost to health-care systems, and increase the complexity of the treatment.

"It is useless to take more medicine if it is not benefitting the individual because it increases the risk of side-effects," said Mehreen Zaman, a volunteerat the Peel HIV/AIDS Network's booth.

Virolgic failure

After an average of three years of follow-up, about 25 per cent of both groups reached virologic failure, in which the drugs could no longer reduce levels of virus in the blood. The researchers defined virologic failure as two consecutive measurements of HIV RNA levels of 200 copies per millilitre.

In a separate analysis, the team found non-Hispanic black patients who reported not taking the drugs as directed had a nearly two-thirds higher rate of virologic failure than other groups.

Blacks were not less adherent than whites, but a lack of social support for taking the drugs may play a role, Gulick said.

The participants were representative of the U.S. population, he said. More than half of the patients studied were black or Hispanic and almost 20 per cent were female.