Genetic Test to Aid Medication Selection

A big advance in personalized medicine is a new DNA microarray test that allows doctors to consider genetic information from patients in order to select the most appropriate medication and dosage for a wide variety of conditions, such as heart disease, cancer, and psychiatric disease. The test is the first such test to be cleared by the U.S. Food and Drug Administration (FDA).

The test is performed using DNA extracted from a patient's blood. The DNA sequence is determined by the sequence of the probe molecule to which DNA is most similar. The test analyzes one of the genes from a family called cytochrome P450 genes, which break down certain drugs and other compounds in the liver. Variations in the gene can cause a patient to metabolize certain drugs more quickly or more slowly than average, or in some cases not at all. The specific enzyme analyzed by the test is cytochrome P4502D6. The test is intended to be used along with clinical evaluation and other tools to determine the best treatment options for patients.

Called AmpliChip Cytochrome P450, the genotyping test was developed by Roche Molecular Systems, Inc., (Pleasanton, CA, USA) and is cleared for use on the GeneChip microarray instrumentation system of Affymetrix, Inc. (Santa Clara, CA, USA).

"Physicians can use the genetic information from this test to prevent harmful drug interactions and to assure drugs are used optimally, which in some cases will enable patients to avoid less-effective or potentially harmful treatment choices,” noted acting FDA commissioner Lester M. Crawford.