Although HIV cocktail therapies have decreased AIDS-related deaths over the years, resistant strains of the virus are emerging, as highlighted by two studies published in the Journal of the American Medical Association. Visible Genetics Inc.'s TruGene HIV-1 genotyping assay and ViroLogic Inc.'s PhenoSense HIV phenotyping assay offer the ability to detect such treatment-resistant strains of the virus. Both technologies have their respective strengths and weaknesses and ultimately could be used in combination to select optimal treatment regimens.

In last week's JAMA studies, researchers at ViroLogic (South San Francisco, Calif.) reported that 28 percent of 141 newly infected HIV patients had