Quest Diagnostics reports the availability of a test to help determine whether a patient with a history of HIV drug resistance will respond to the latest class of HIV antiretroviral therapies. The HIV-1 Coreceptor Tropism Test reports results in approximately half the time of the nearest competing test, Monogram’s Trofile HIV tropism test, according to Wendy H. Bost, spokesperson for the company.
HIV co-receptor tropism refers to the preference of strains of HIV to bind to, activate, and infect cells based on the type of co-receptor on the cell’s surface. The newest class of antiretroviral drugs, called entry inhibitors, targets the tropism process involving one or both co-receptors, CCR5 or CXCR4, found on CD4 cells. Guidelines from the U.S. Department of Health and Human Services recommend tropism testing prior to the start of a CCR5 inhibitor like Pfizer’s Selzentry.
“CCR5 antagonist entry inhibitors have given physicians new options for treating thousands of patients with HIV who have shown resistance to earlier HIV therapies,” remarks Jay G. Wohlgemuth, M.D., vp of Science and Innovation, Quest Diagnostics. “Yet they are only suitable for about half of these patients due to the different ways that the virus tries to infect cells.
“With our new tropism test, we expect to report results within seven days of receiving a patient specimen, compared to the leading commercial HIV tropism test, which requires two weeks of processing time once a sample is received. Considering that tropism status can change in as little as a few weeks in patients with a history of HIV drug resistance, faster results potentially translate into earlier initiation of efficacious therapy.”
Quest Diagnostics, using samples from patients with a history of drug resistance, found that the HIV-1 Coreceptor Tropism test demonstrated 74% agreement with Trofile and 74% agreement with SensiTrop™ II, a genotypic tropism test previously available from Pathway Diagnostics. The SensiTrop II test, which is no longer commercially available, was 73% percent in agreement with Trofile.
Quest Diagnostics had offered a prior version of the SensiTrop test through a license with Pathway Diagnostics before acquiring the company during the fourth quarter 2008. The company’s new HIV-1 co-receptor test employs a novel molecular-based technology developed by Quest Diagnostics scientists.
In addition to HIV tropism testing, Quest Diagnostics’ services range from HIV diagnostic testing to monitoring HIV viral load, determining a viral genotype, and testing for the HLA-B*5701 genetic marker as an aid in predicting a hypersensitivity reaction to GlaxoSmithKline’s Ziagen.
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