MOLECULAR DIAGNOSTICS took a big step forward in December. During the month, the Food and Drug Administration (FDA) cleared the first microarray instrument system and microarray-based laboratory test for clinical use.
The FDA announced on December 23, 2004 that it had cleared the Gene-Chip® System (GCS) 3000Dx for clinical use. Affymetrix, Inc. of Santa Clara, California manufactures this instrument system.
Also on the same day, the FDA announced clearance of the AmpliChip™ Cytochrome P450 Genotyping Test for clinical use. This test kit is manufactured by Roche Molecular Systems, Inc., based in Pleasanton, California.
Cleared In Europe and USA
Both products received regulatory clearance in Europe this September. With regulatory clearance on both continents, the Roche/Affymetrix system becomes the first microarray system and diagnostic test to reach the clinical marketplace.
Because the Affymetrix AmpliChip test instrument has cleared this regulatory step, it becomes a favored technology platform upon which other proprietary microarray tests can be run. Lab managers and pathologists can expect a variety of biotech and IVD companies to develop diagnostic tests specifically designed to run on the AmpliChip instrument. That makes FDA clearance for the test kits easier, faster, and cheaper.
As an example, within days of the news that the FDA had cleared the GeneChip instrument for clinical use, Affymetrix announced a licensing deal with Veridex, LLC, a business unit of Johnson & Johnson Company. Veridex plans to develop cancer markers to run on the GeneChip instrument system.
For Roche, the FDA’s decision allows it to move other microarray tests through the development pipeline and into the clinical marketplace. This first test, the P450 Genotyping Test, extracts DNA from a patient’s blood. It searches for 31 different polymorphisms in the cytochrome P450 gene. These polymorphisms identify genetic variations which affect whether a patient’s liver can metabolize certain drugs fast, slow, or not at all.
The market for this test appears to be substantial. The polymorphisms it detects affect metabolization of about 25% of all prescription drugs. This test represents its own milestone, because it is the first down payment on the promise of pharmacogenomics—the ability to determine a patient’s genetic predisposition to benefit (or not) from a specific drug and anticipate whether or not it may cause clinically significant side effects.
The importance of this development should not be underestimated. As clinicians begin to use this test, and the other tests expected to follow, it will be necessary for laboratories to acquire microarray technology and offer molecular tests to their physicians. That will require significant investments of capital and the need to have lab staff with the technical skills required to perform these tests.