By Frances Bishopp

Specialty Laboratories Inc., a provider of HIV-PCR testing services, said its newly introduced HIV-1 GenotypR Plus blood test will pinpoint resistance-associated HIV mutations for each of the FDA-approved antiviral drugs, such as nucleoside analogues and protease inhibitors.

HIV-1 GenotypR PLUS uses PCR technology and automated DNA sequencing, called genotyping, to identify specific HIV gene mutations in a patient's virus. It then matches them to known drug-resistant HIV viruses to identify similar resistance-associated mutations, Herm Reyes, director of medical communications at the Santa Monica, Calif.-based laboratory, told BioWorld Today.

Specialty Laboratories is a clinical reference laboratory which provides specialized testing services to the medical community. The HIV-1 GenotypR Plus test is performed only at the laboratory and is not sold as a kit.

"This is the first commercially available test to detect resistance mutations," Reyes said.

Recent studies have shown a combination of AIDS drugs is more effective than a single-drug therapy when treating patients with HIV and AIDS. The health of such patients, however, is jeopardized if they develop resistance to one or more of the drugs in the cocktail.

Currently, when a patient's viral load increases during cocktail therapy, doctors must guess which of the three or four drugs the virus has become resistant to and which drugs are still effective.

Because the test is being performed only at a lab, it does not require FDA approval and already is in use, Reyes said. The test costs $400.

Antimicrobial resistance has long been a problem with compounds such as penicillin, Reyes said. "In HIV, the currently held notion is if you treat a patient with antiviral drugs and you fail to suppress viral replication overall, resistance is a problem that could potentially develop in a patient," Reyes explained.

The test would be used as a baseline measure when the patient first tests HIV positive and before the physician begins the treatment regimen. The test could be given again if, after the patient is on an antiviral regimen, he or she suddenly has an increase in viral load.

"At that point," Reyes said, "the physician would have reason to suspect that resistance has developed. This test could also indicate to which drug the patient has become resistant and which drugs are still therapeutic options."

With this test, Reyes said, the doctor can make more informed decisions regarding the patient's treatment rather than taking a wait-and-see approach. It saves money and can be of great benefit to the patient, he said. *