HIV Regimen Has Fewer Side Effects
Study finds tenofovir effective but better in long run
SUNDAY, July 11, 2004 (HealthDayNews) -- The first study of its kind has found that two different combinations of antiretroviral drugs are equally effective in battling infection with the AIDS virus.
One drug, however, appears to be better with regard to long-term effects on cholesterol levels and the nervous system.
A second study has found that combining two drugs did not further reduce the transmission of the virus from mother to child at birth.
Both studies appear in the July 14 issue of the Journal of the American Medical Association, a themed issue on HIV/AIDS. The studies were released early because the findings will be presented at the 15th International AIDS Conference that begins Sunday in Bangkok.
According to the authors of the first article, highly active antiretroviral therapy (HAART) has transformed HIV infection into a chronic and manageable disease. The challenge is to manage adverse effects, long-term toxicity and complex dosing schedules.
In this study, led by Dr. Joel E. Gallant of Johns Hopkins University School of Medicine, 602 HIV-positive patients in the United States, South America and Europe who had not been treated before were randomized to receive either tenofovir disoproxil fumarate (DF) or stavudine. Both drugs were given in combination with lamivudine and efavirenz. The trial is the first large, three-year, randomized, double-blind trial of antiretroviral drugs in patients who had never before been treated. It was funded by Gilead Sciences, which makes tenofovir DF.
At the end of 48 weeks, 80 percent of the patients receiving tenofovir DF and 84 percent of patients receiving stavudine had acceptable levels of HIV in their blood.
The difference lay in side effects, specifically with regard to cholesterol levels and peripheral neuropathy such as pain or numbness in the feet or legs.
"They showed reasonably that the drugs in terms of their ability to squash the virus are about the same," said Dr. Charles Gonzalez, an infectious diseases specialist and a professor of medicine at New York University School of Medicine. "This shows that this regimen [tenofovir] is fine and dandy. It's just as good as the standard of care and, at the same time, long-term, it might have less complications."
The second study, led by Taha E. Taha of Johns Hopkins' Bloomberg School of Public Health, looked at whether the addition of another drug would reduce further the risk of mother-to-child HIV transmission at the time of birth.
Pregnant women are not routinely tested for HIV in Africa, meaning that many aren't getting recommended antiretroviral therapy during pregnancy. They and their babies may also not get the suggested dose of nevirapine at the start of labor and after birth.
Theorizing that two drugs might be better than one, the study authors tried giving both nevirapine and zidovudine. A randomized trial was conducted at six clinics in the African nation of Malawi between April 1, 2000, and March 15, 2003. Eight hundred ninety four infants born to HIV-positive women were randomly assigned to receive either nevirapine or nevirapine plus zidovudine for one week.
At the end of six to eight weeks, 14.1 percent of infants who had received nevirapine alone and 16.3 percent of those receiving the combination had HIV. After excluding infections that occurred at birth, the risk of transmission at this time frame was 6.5 percent for the single-drug group and 6.9 percent for the combination group.
"Adding the second drug didn't make any difference at all, not an iota of difference," Gonzalez stated. "Everyone predicted that it would have done a little bit better but, obviously, in a resource-limited setting in the Third World where you are using single drug agents, it's not worth the cost."
The U.S. Centers for Disease Control and Prevention has more on HIV and AIDS.