Sidling up to Roche Molecular, Abbott and Celera Diagnostics have received the CE Mark certification for their real-time PCR HIV viral load assay, and will begin competing against the market leader in Europe this week.
The new test runs on Abbott's m2000 real-time PCR instrument, which has also received a CE Mark, but has not yet been submitted for clearance with the FDA, said Don Braakman, an Abbott spokesperson, adding that the company will be submitting the test for US approval in 2005.
"We are in the process of launching this test this week" in Europe, Braakman said. Pricing information was not yet available, he said.
If the Abbott/Celera real-time PCR test is to get a foothold in the market — which is already well populated by conventional PCR-based viral-load tests from the likes of Roche and Bayer — it will have to offer a significant advantage. Real-time PCR is a faster test than conventional PCR because amplification and detection occur simultaneously, said Braakman. Also, "there's less of a chance with real-time PCR for contamination to occur," resulting in more reproducible results, he said. Bayer sells a branched-chain DNA HIV viral-load assay that was cleared by the FDA in 2003.
But Roche also touts these advantages for its own real-time PCR HIV load test, so the key point of comparison appears to be price.
Real-time PCR testing "has some advantages, but I wouldn't say 'significant advantages,'" said Jorge León, head of Leomics, a Princeton, NJ, molecular-diagnostics consulting firm. While at Quest Diagnostics, León's group created the laboratory-testing giant's HIV viral-load test. In addition to being faster, real-time PCR assays are generally more cost-effective, and higher-throughput, he said.
The major player in the viral load market, Roche received a CE Mark for its real-time PCR TaqMan HCV, HBV, and HIV-1 tests in April, and that diagnostic is now available in the European Union as an in vitro device. Roche's HIV viral-load test runs on the company's Cobas TaqMan platform.
Roche's conventional PCR test has been available since the early 1990s through the company and through LabCorp, the largest diagnostic lab company in the United States.
Viral-load testing is a key, if somewhat ignored, segment of pharmacogenomics. With information on the blood concentration of virus particles, doctors can infer the effectiveness of treatment. Given once every few months, the test can signal a doctor to change an anti-HIV drug regimen when the test reveals viral load to be increasing, for example. Likewise, a sustained, low level of viral load is usually interpreted as a signal that current therapy is working. Viral load information is also often used to produce a prognosis for the amount of time until the onset of AIDS.
The viral load tests made by Roche and Abbott and Celera are not capable of identifying particular viral strains, information that can reveal which drugs may work best in a particular patient. The companies offer other products for that purpose. Viral-load tests are generally manufactured to detect as many strains as possible with equal efficiency, in order that the total concentration of virus can be determined.
"The HIV viral load [tests] are probably one of the most important tests in molecular diagnostics" for public health reasons, said León.
Companies should price such tests so that they are broadly affordable, encouraging their adoption around the world, for reasons of market share and good medicine, said León. "Price is going to be a fundamental issue here," he said. "In Europe and Latin America … you see that the HIV patients do not get the viral load [tests] with the frequency that is required to monitor progression of disease."
Price will also help determine the total size of the market. In the US, "literally, every HIV patient gets HIV viral load [tests], and they get [them] about 2.5 to three times per year," said León. As recently as three years ago, however, only about 60 percent of European HIV patients received the diagnostic, León estimated. Testing rates in developing countries are even lower, he said.
As of 2003, there were slightly fewer than 1 million HIV infections diagnosed in the United States, according to the US Centers for Disease Control and Prevention.
"When I developed this test for Quest in 1995, we were thinking about recommending doctors to use this test at least once a year, but time has shown that monitoring for viral loads once every three months is much more effective," said León. "This is where the price of the technology is going to play a role," he said.
"I don't know what the policies [are] of Abbott and Celera around price," said León. "I can tell you that real-time PCR, as a technology, is more amenable to cost reduction and to automation than conventional PCR," he said.
— Chris Womack ([email protected])