An FDA advisory committee, without taking a formal vote, agreedthat Roche Molecular Systems Inc.'s polymerase chain reaction(PCR) test to measure HIV RNA levels is worthy of approval.
The Amplicor HIV Monitor would provide the first quantitative testmonitoring HIV levels in patients by using PCR technology. Recentstudies showed the amount of HIV RNA in the blood is a betterpredictor of disease progression and survival than CD4 T cell counts.
Roche Molecular Systems, a Branchburg, N.J., subsidiary ofHoffmann-La Roche Inc., now is waiting for the FDA's decision.Another Amplicor product, for diagnosing tuberculosis infection, alsois awaiting agency approval. An Amplicor chlamydia test has beenmarketed since 1993.
"This test is vitally important to the AIDS treatment picture," saidPaula Evangelista, director of public policy for Roche MolecularSystems. "They key is getting the test available for broad use in theHIV-infected community."
The test is reproducible at viral loads as low as 400 copies permilliliter of plasma, and has an upper limit of 750,000 copies. Thatsensitivity allows quantification of HIV RNA through all phases ofinfection. The specificity of the test was 100 percent in a study on495 seronegative blood donors.
The test can be used as a prognostic indicator of disease progressionand to monitor the effectiveness of antiretroviral therapy. Evangelistasaid Roche agreed with the panel's belief that more clinicalexperience is needed before the test is used for patient management.
In Europe, Roche already is marketing the Cobas Amplicor, anautomated system that does both amplification and detection. Itcurrently includes assays for tuberculosis, hepatitis C, chlamydia andgonorrhea.
If approved, the HIV Monitor test would be sold to hospitals andlaboratories. Eventually Roche would like to add it to the CobasAmplicor system.
Another test measuring HIV levels is under FDA review. ChironDiagnostics, of Emeryville, Calif., is seeking approval of theQuantiplex HIV RNA Assay, a branch DNA assay. n
-- Jim Shrine
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