New HIV tests look to speed up viral load analysis

By Dr Matt Wilkinson

- Last updated on GMT

Related tags: Abbott

Abbott Laboratories and Roche Diagnostics have both had HIV-1 tests
approved by the US Food and Drug Administration (FDA) that should
allow clinical laboratories to deliver viral load results faster.

The new assays feature automated systems for sample preparation and data analysis, and can be used to monitor the effects of antiretroviral drugs in both clinical and research settings. Abbott estimates that their latest offering could reduce the hands-on time required to prepare the DNA samples for analysis by 75 per cent. The tests can be also be used to help clinicians assess patient prognosis by measuring baseline HIV-1 RNA levels. The World Health Organisation (WHO) estimated there were 39.5m HIV sufferers in 2006, with over 4m people infected in that year. According to a Datamonitor report entitled Commercial Insight: HIV - Change of guard​, the HIV drug market generated sales of $7.4bn in 2005. The new tests are both based on real-time polymerase chain reaction (RT-PCR) and are fully automated to allow the rapid quantification of very low virus levels in blood samples. With over 2 million viral load tests being conducted in the US alone, the need for fully automated test systems is clear. Roche's test combines the Cobas AmpliPrep automated sample preparation instrument with the Cobas TaqMan analyser for automated RT-PCR amplification and detection "The new test system provides innovative options for combining a more sensitive HIV test with full automation that simplifies state-of-the-art molecular diagnostic testing,"​ said Severin Schwan, CEO of Roche Diagnostics. Roche currently has a Hepatitis C virus test under review by the FDA. Abbott's RealTime HIV-1 assay, approved in the EU in July 2005, was designed to detect and measure levels of all known genetic variations HIV circulating in a patient's blood, including the three major groups of HIV-1 and non-B subtypes. "As the viral diversity of HIV-1 continues to increase, the need for highly sensitive tests to monitor patient response to antiviral therapies becomes even more important,"​ said Dr John Robinson, senior director of research and development at Abbott Molecular. The company believes that the new test, developed as part of its alliance with Celera, can "offer substantial productivity and performance advantages to customers performing these tests"​. The test is designed for use on the new m2000 system which was designed to remove the laborious steps usually involved with these measurements. The system has a broad dynamic range and can identify HIV-1 in plasma at levels as low as 40 RNA molecules per ml and up 10m molecules per ml. If the viral load in a patient's blood increases, it indicates that a resistance-conferring mutation has occurred. Celera's Viroseq HIV-1 genotyping system can then be employed to discover the genomic mutations that confer resistance to specific types of antiretroviral drugs. Abbott currently has portfolio of assays for the m2000 system that are CE-marked in the EU, including tests for HCV, Chlamydia trachomatis (CT) and a combination test for CT/Neisseria gonorrhoeae.

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