Genes guide medication decisions, potential treatment

The first fruits of genomic medicine are being enjoyed by North Carolina patients on a common anti-clotting drug but soon could include many other drugs and one day people facing radiation or with a difficult-to-treat form of breast cancer, researchers said.

At a conference Thursday and Friday in Augusta, researchers will talk about the practical applications of genomic medicine (the genome is the human genetic code) that allows for more personalized care. The 2012 Southern Translational Education and Research Conference is being put on by Georgia Health Sciences University Cancer Center and the University of Georgia College of Pharmacy’s Clinical & Experimental Therapeutics Ph.D. Program and Center for Drug Discovery.

Among those speaking will be Dr. Howard L. McLeod, a professor of medicine and pharmacy at the University of North Carolina Institute for Pharmacogenomics and Individualized Therapy.

For the past few years, the university has teamed with community pharmacies in Chapel Hill to look at patients taking the anti-platelet drug Plavix, or clopidogrel, the ninth-most commonly prescribed drug in the U.S., according to the latest ranking from Drugs.com. The patients are offered a test for the gene that encodes the enzyme that breaks down the drug to make it active. Those with certain variants of the gene that would make them poor metabolizers of the drug can then be offered the choice, based on their risks, of higher doses or a different drug that doesn’t use that enzyme to work.

“In terms of the vast majority of people, it seems to be that medicines, either choosing the right dose or choosing the right medicine, is going to be one of the first places where the average person realizes that the genome is useful,” McLeod said. That also can apply to other drugs and other genes, he said.

“We’re working toward a panel, initially a relatively small panel affecting about five different genes, where we clearly know what to do with the results,” McLeod said. “And then there are a larger group of about 60 genes where we think we know what to do with the results. And of course you have the whole genome as the end result.”

In breast cancer, for instance, chemotherapies are already prescribed based on whether the cancer has receptors for estrogen, progesterone or the HER2 gene, said Dr. Lesleyann Hawthorn, the director of shared resources for the GHSU Cancer Center, who does genome sequencing, or decoding.

The university is also collaborating with Savannah River Site to sequence radiation-resistant bacteria to see whether humans have any genes in common that could be exploited, Hawthorn said. Doing that kind of sequencing in humans is becoming much faster and cheaper all the time – the center can turn around the gene-encoding portion of a person’s genome in 48 hours for around $2,000, she said, and it will become even cheaper and more common soon.

“Probably within the next five to six years, everyone will get their DNA sequenced,” she said.