Abbott has received a supplemental Premarket Approval from the US Food and Drug Administration for its recently introduced RealTime HIV-1 viral load test. The approval allows Abbott to market a number of enhancements to the test, including a new design feature that will give laboratories the flexibility to perform HIV-1 viral load tests with smaller amounts (0.6 mL) of blood plasma. Abbott markets the m 2000 system and a menu of tests throughout the world as part of a strategic alliance with Celera.
"It can be challenging to obtain blood samples from some people, particularly critically ill patients," said Timothy Stenzel, M.D., Ph.D., medical director, Abbott Molecular. "This improvement will give labs the ability to use a smaller sample size while still maintaining the highest sensitivity and precision of any HIV-1 viral load test. It's easier on the patient and at the same time better for the lab."
Initially approved in the United States on May 11, 2007, the RealTime test, based on real-time polymerase chain reaction (PCR) technology, is the most sensitive HIV-1 viral load test available and the only test of its kind validated to detect and quantitate (precisely measure) the common strains of HIV-1 as well as all known genetic variations of the virus, including group O, group N, and non-B subtypes.
The Abbott assay has a broad dynamic range, capable of quantitating HIV-1 in plasma down to as few as 40 RNA copies per mL, surpassing the standard of care in diagnostic sensitivity of 50 copies per mL. Also, unlike other assays, the Abbott RealTime HIV-1 test targets the highly conserved pol integrase region of the HIV-1 genome, giving the test its unique ability to detect and measure all known genetic variations of the virus.
"Because of what we now know about the emergence of variant strains of HIV-1 in the United States and other countries, it is critical for clinicians to monitor for non-B subtypes as well as group O and group N strains of HIV-1 in their patients," Stenzel said. "It is imperative that an assay with reliable subtype performance be used to guide antiretroviral therapy so as to not be lulled into thinking a patient is responding well to therapy when, in fact, they are not. The RealTime assay also correlates well with other viral load tests, which suggests that it is not necessary for physicians to re-establish a baseline viral load for their patients when changing to this test," he said.
The company also received supplemental approval to increase the testing capacity of the Abbott m2000 automated instrument for use with the RealTime HIV-1 viral load test. The enhanced system can process up to 96 specimens in a batch and 192 specimens in one laboratory shift. This represents the highest throughput available for an HIV-1 viral load test using real-time PCR technology.
"We're pleased to offer these important enhancements, which we believe reinforces the clinical advantages of the RealTime HIV-1 viral load test," said Stafford O'Kelly, president, Abbott Molecular.
Additional products in development in the United States for the Abbott m2000 system include assays for hepatitis C virus, hepatitis B virus, chlamydia and gonorrhoea. The m2000 system and a full menu of infectious disease tests are available in the European Union as CE-marked products.
Quantitative measurements of HIV-1 levels in blood have greatly contributed to the understanding of the process by which the virus infection leads to disease and has been shown to be an essential parameter in prognosis and management of HIV infected individuals. Decisions regarding initiation or changes in antiretroviral therapy are guided by monitoring plasma HIV-1 levels or viral load, CD4-T cell count, and the patient's clinical condition. The goal of antiretroviral therapy is to reduce the virus in plasma to below detectable levels.
The RealTime test is intended for use in conjunction with clinical presentation and other laboratory markers as an indicator of disease prognosis and for use as an aid in assessing viral response to antiretroviral treatment as measured by changes in plasma HIV-1 RNA levels. The assay is not intended to be used as a donor-screening test for HIV-1 or as a diagnostic test to confirm the presence of HIV-1 infection.