Reporting in the latest issue of The New England Journal of Medicine, the researchers showed that after one year of treatment, a regimen of antiretroviral pills, called tenofovir DF (Viread) and emtricitabine (Emtriva), plus efavirenz (Sustiva), led to 14 percent more patients being able to suppress levels of the virus.
At the same time, they encountered fewer problems of anemia, fatigue and nausea compared to use of another widely used combination of antiretrovirals, zidovudine and lamivudine (AZT and 3TC, or Combivir), plus efavirenz.
"The implications are quite clear for patients with HIV who are about to start therapy: The simple combination of tenofovir and emtricitabine, plus efavirenz, is likely to be highly potent with minimal side effects or long-term toxicity," said the study's lead author, Joel Gallant, associate director of the AIDS Service at The Johns Hopkins University School of Medicine.
He noted that this regimen became even simpler in 2004, when tenofovir and emtricitabine were combined into a single pill, called Truvada.
Tenofovir DF and emtricitabine are relatively new drugs, approved by the US Food and Drug Administration (FDA) in 2001 and 2003 respectively.
Zidovudine was the first antiretroviral drug, approved in 1987, and lamivudine became available in 1995.
Since 1998, zidovudine and lamivudine have been available in a single-pill formulation called Combivir, which is prescribed as one pill taken twice daily.
Gallant cautioned that the latest results may not apply to those patients already on zidovudine-lamivudine therapy and experiencing no problems.
However, he pointed out that after the first year of the study, expected to continue for another two years, data already show early evidence of lipoatrophy, or fat loss, in patients taking this regimen.
Lipoatrophy is a known complication of some HIV medications that can lead to disfiguring changes in body shape.
The researcher said that if fat loss gets worse during the remainder of the study in patients taking the zidovudine-lamivudine regimen, this would support switching to the tenofovir-emtricitabine regimen.
"Both treatments are effective," Gallant noted. "But this study shows that we can do better, with fewer side effects and greater simplicity."
The US Centers for Disease Control and Prevention estimates that 40,000 Americans are newly infected each year with the virus that causes AIDS.
Another quarter of a million people already have HIV and are unaware of their infection and need for treatment.