About AIDS

Because it reproduces very fast and makes careless mistakes, HIV naturally mutates and grows resistant to any given drug over time. Perhaps 20-60% of HIV positive people have a virus that resists at least one of the 15 drugs. So how can poz people tell if a drug is going to work as part of their treatment cocktail? There are two types of resistance testing: Phenotype testing challenges a virus sample with a given drug to see if it grows despite the treatment; and genotype tests examine the sample virus' actual genetic makeup, looking for specific mutations known to likely cause resistance to a drug. Both tests are slow (2-4 weeks), expensive ($250-900), sometimes not covered by insurance, and too technologically complex for all but a few labs.

Even so, resistance tests should always inform treatment decisions, given the $1000-plus monthly cost of HIV drugs and the suffering caused by ineffective treatment.

Recently, however, the FDA approved Visible Genetics' Trugene, the first test to identify resistance-causing mutations quickly. A blood sample is sent to one of 130 Trugene-trained affiliate labs, where the viral genome is computer-decoded. All mutations are identified and matched to more than 70 mutations currently known to cause resistance to specific AIDS drugs. A year of FDA review found Trugene to be 98% accurate, and newly discovered mutation data can be quickly added to the computer software to keep Trugene current.

Especially because Trugene takes only three days and is competitive at $300-$500, this remarkable genetic testing process can be an important tool in helping physicians choose the most effective treatment combination for each patient, saving lives and money at the same time.