SensiTrop HIV Co-receptor Tropism Assay Now Available

Armen Hareyan's picture
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Pathway Diagnostics announces nationwide availability of SensiTrop, its proprietary molecular heteroduplex tracking assay (HTA) for determining the co-receptor tropism status of HIV infected patients. Pathway performs the SensiTrop assay in its CLIA approved laboratory on samples received from Mayo Medical Laboratories and other soon-to-be named national laboratories.

Recently Pfizer Inc. and the FDA announced the approval of Selzentry (Maraviroc), the first in a novel class of anti-retroviral drugs based on blocking the CCR5 co-receptor of HIV. Selzentry, in combination with other antiretroviral agents, is indicated for treatment-experienced adult HIV patients with only CCR5-tropic HIV-1 detectable who have evidence of viral replication, and HIV-1 strains resistant to multiple anti-retroviral agents. The FDA label states that when initiating therapy, tropism testing and treatment history should guide the use of Selzentry.

"Pathway is pleased to introduce this second generation diagnostic HIV tropism assay nationwide, providing clinicians a fast, sensitive and economical testing alternative to the currently available biological HIV tropism assay," said Walter Narajowski, Pathway Diagnostics President and CEO. "This timely introduction of SensiTrop is a perfect example of Pathway's strategy to license proprietary biomarkers, develop them, and rapidly commercialize them with diagnostic partners."

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SensiTrop is a molecular based assay designed and demonstrated to be highly-sensitive in detecting CXCR4-tropic HIV in patient samples that contain as little as 1% CXCR4. "The combination of SensiTrop's high-sensitivity and rapid turn-around-time (less than 7 days) will be extremely valuable to HIV physicians and patients when utilizing co-receptor tropism status to guide the use of Selzentry," said Terry Robins Ph.D., Vice President of Research and Development at Pathway Diagnostics.

About HIV Co-receptor tropism and the SensiTrop assay

The ability of the HIV virus to infect different cell types utilizing different cell surface receptors is referred to as HIV co-receptor tropism. One type of HIV that utilizes the CCR5 co-receptor has been shown to be blocked by CCR5 antagonist drugs such as Selzentry. A different type of HIV that utilizes the CXCR4 co-receptor is not blocked by CCR5 antagonists. Therefore, determining the tropism status of HIV-infected patients has been indicated by the FDA before initiating CCR5 antagonist therapy.

Pathway's SensiTrop assay is a molecular hybridization technique based on heteroduplex tracking technology developed by Dr. Barbara Weiser and Dr. Harold Burger's laboratory at the Wadsworth Center, New York State Department of Health, Albany NY. Heteroduplex tracking technology interrogates the complete HIV V3 loop, detecting sequence differences that determine whether the patient's HIV utilizes either the CXCR4 or CCR5 co-receptor. SensiTrop, like other molecular based assays, is highly sensitive and rapid to perform.

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