Genetics

THE RIGHT DRUG, THE RIGHT DOSE

Pharmacogenetic researchers study individual response to drugs in two ways: drug response and adverse drug reaction. For example, some patients don’t get the desired response from a therapeutic drug, while others have a strong negative reaction to it. Several factors may contribute to these reactions, such as age, gender and underlying disease. Pharmacogenetic researchers focus on the role of genetic inheritance in drug response.

One example of the power of pharmacogenetics was discovered at Mayo Clinic, and resulted in a now-standard clinical test related to a childhood leukemia drug called 6-mercaptopurine. Researchers found that as a result of genetic inheritance, 10 percent of people have a decrease in their ability to metabolize this drug, and one out of every 300 people can’t metabolize the drugs at all. In effect, their bodies cannot handle normal doses of the drug.

People who cannot metabolize the drug become very sick when treated with standard doses, because the standard dose is 10 times too much for these people. Researchers then developed a blood test to determine a patient’s enzyme activity, which allowed them to tailor the dose of the drug to the patient’s inherited ability to metabolize it.

Pharmacogenetics research translates very quickly to changes in treatment; new genomic information is very rapidly being converted into information that will have an impact on clinical care.

For additional information on pharmacogenetics research, see Current Projects.