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Roche AmpliChip Cytochrome P450 Genotyping test and Affymetrix GeneChip Microarray Instrumentation System - K042259

This is a brief overview of information related to FDA’s clearance to market this product.

Product Name : Roche AmpliChip Cytochrome P450 Genotyping test and Affymetrix GeneChip Microarray Instrumentation System
Manufacturer: Roche Molecular Systems, Inc. and Affymetrix, Inc.
Address: 4300 Hacienda Dr. , Pleasanton , CA 94588 and 3380 Central Expy. , Santa Clara , CA 95051
Clearance Date: December 23, 2004
Clearance Letter: http://www.fda.gov/cdrh/pdf4/k042259.pdf

What is it? The Roche AmpliChip Cytochrome P450 Genotyping test for use on the Affymetrix GeneChip Microarray Instrumentation System is a new laboratory test system that will help doctors personalize treatment options for their patients. Doctors can use a patient’s genetic information to help them determine appropriate drugs and doses to prescribe. This will help minimize harmful drug reactions and prevent patients from being improperly treated with sub-optimal doses.

This system uses DNA extracted from a patient’s blood to detect certain common genetic mutations that alter the body’s ability to break down (metabolize) specific types of drugs. The enzyme produced from the gene that is tested, called cytochrome P4502D6 (CYP4502D6), is active in metabolizing many types of drugs including antidepressants, antipsychotics, beta-blockers, and some chemotherapy drugs. Variations in this gene can cause a patient to metabolize these drugs abnormally fast, abnormally slow, or not at all. For example, the same dose that is safe for a patient with one variation might be too high (and therefore toxic) to a patient with a different variation who cannot metabolize the drug.

With genetic information for this gene, many harmful reactions resulting from inappropriate dosing and treatment may be significantly reduced as clinicians can adjust the patient’s regimen accordingly.

How does it work? A doctor orders the genetic test in patients to gather information on the predicted metabolic activity of their enzyme encoded by CYP4502D6.

A sample of blood is collected and taken to the lab.
The lab extracts DNA from the blood sample.
The lab processes and applies the DNA to the Cytochrome P450 Genotyping test.
The GeneChip Microarray Instrumentation System reads the test.
The genetic result for the Cytochrome P450 Genotyping test is sent to the doctor.
The doctor uses the Cytochrome P450 genetic test results, clinical evaluation and other lab tests as an aid in individualizing patient treatment options.

When is it used? The AmpliChip Cytochrome P450 Genotyping System is used to help a clinician determine if a patient has mutations in their CYP4502D6 gene that may affect their ability to metabolize certain drugs.

You should discuss these test results with your doctor because your body’s ability to metabolize a range of drug classes may be affected. This test is not a substitute for your doctor’s judgement and clinical experience. The test system is designed to aid the doctor in making individualized treatment decisions.

What will it accomplish? The AmpliChip Cytochrome P450 Genotyping System may help the doctor determine if a patient is at risk of adverse drug reactions or sub-optimal drug response.

When should it not be used? The AmpliChip Cytochrome P450 Genotyping System should not be used:

As the only test to determine specific drug dose. Other clinical information and patient history should primarily be considered.
To aid in predicting a patient’s drug response for drugs that are not metabolized by the enzyme encoded by Cytochrome P4502D6.
To aid in predicting a patient’s response to drugs for which the mutant Cytochrome P4502D6 phenotype has not been clearly established

Additional information:

FDA Talk Paper: http://www.fda.gov/bbs/topics/news/2004/new01149.html

Information on CYP2D6 allele nomenclature : http://www.imm.ki.se/CYPalleles/cyp2d6.htm

Brief description of Cytochrome P4502D6: http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=124030

Prescription Drug Information: http://www.fda.gov/cder/Offices/DDI/pathfinder.htm

Updated March 8, 2005

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Center for Devices and Radiological Health / CDRH