FDA Approves Genetic Test to Predict Viral Mutations in Response to HIV Drug Treatment

After completing a year of study, the FDA on Wednesday approved the first genetic test to determine whether a patient's HIV infection has become resistant to one or more antiretroviral drugs, the AP/Los Angeles Times reports. Trugene, made by Visible Genetics Inc., was described yesterday by FDA officials as an "important tool" for aiding doctors in choosing the best combination of drugs to treat a patient's HIV infection. HIV is extremely mutable, and 60% of patients with HIV have an infection that is resistant to at least one of the 15 anti-HIV drugs available (AP/Los Angeles Times, 9/28). Until recently, doctors would test patients' viral levels to determine if resistance was growing. A "spike" in the amount of HIV present would indicate that treatment was failing and a new drug combination would be prescribed (AP/Houston Chronicle, 9/27). Using Trugene, doctors can now determine to which drug the virus has grown resistant and can more specifically tailor treatment. Physicians send a patient blood sample to one of 130 labs with technicians trained in the use of Trugene. A computer "decodes" the HIV genes present in the blood, determining the mutations present. A software program then compares those mutations to a chart of the more than 70 known mutations already associated with specific anti-HIV drugs. Doctors receive a lab report containing an analysis of what drugs are likely to be most effective for that particular patient (AP/Wall Street Journal, 9/28). Dr. R. Scott Hitt, president of the American Academy of HIV Medicine, called the test a "major step forward in HIV treatment," but cautioned that it is "only one piece of the puzzle" (AP/Los Angeles Times, 9/28). The test, which is 98% accurate, costs between $300 and $500 per patient and takes three days to complete, according to Visible Genetics President Richard Daly (AP/Philadelphia Inquirer, 9/28). Daly added on CNBC's "Power Lunch" that the potential market for the test in North America alone is "quite large." About 350,000 to 400,000 people in North America are currently receiving treatment for HIV, and a physician will typically alter a patient's drug regimen once or twice a year. Trugene could be used each time to help tailor the treatment to the patient's specific infection. Daly added that the company is developing similar tests for hepatitis B and C treatment (Griffeth, "Power Lunch," CNBC, 9/27).