Beware Genetic Snake Oil

Kathy Hudson is the founder and director of the Genetics and Public Policy Center at Johns Hopkins University. In "A Case Study of Personalized Medicine," published today in the journal Science, Hudson and her colleagues argue that the rapidly expanding world of genetic testing needs far greater oversight. Hudson spoke with NEWSWEEK's Claudia Kalb. Excerpts:

NEWSWEEK: Your center reports that there are now genetic tests for more than 1,500 diseases and conditions. Examples?
Kathy Hudson: Most of them are for rare diseases that are hard to pronounce. They range from tests for birth defects and mental retardation to tests for various types of cancers, like retinoblastoma, breast cancer and colon cancer. And there are some tests for diseases that used to be considered quite fatal but are getting better with new therapies. Cystic fibrosis. Sickle cell anemia. Tay-Sachs. These are mostly genetic tests for single gene disorders, which means that if you have mutation in that gene, you will, or you're very likely to, have or develop that disease.

What else is out there?
There's another category of tests, which is what we wrote our paper about, an area where there's an enormous amount of enthusiasm. And there should be. This is the whole area of personalized medicine or pharmacogenetics. At the end of television ads for drugs, you hear somebody in a low voice saying, "This drug may cause dizziness or death." If you could figure out the genetic markers associated with how well you'll respond and whether or not you're at risk for adverse effects, that could be a phenomenally wonderful thing and it could save a bazillion dollars in health-care costs.

Tell us about your case study. What did you find?
We did a case study of genetic tests for a family of enzymes called CYP450. CYP450 genes are involved in the metabolism of SSRIs, which are drugs prescribed to treat depression. While these genes clearly play a role, there are not yet clinical studies showing that CYP450 genetic testing is beneficial for SSRI selection and dosing. Despite this lack of scientific evidence, what we found was that companies were making very specific claims to consumers that were either incomplete or blatantly false and misleading. They were claiming that CYP450 genetic testing was required in order to select the right SSRI and to determine the appropriate dose. This is unproven. Some of these companies are selling the tests directly to consumers over the Internet, so there's no health-care intermediary, no gatekeeper to prevent inappropriate testing or misinterpretation of test results.

Where's the oversight? Is the FDA involved?
There is an FDA-cleared test for CYP450. In this particular case the FDA verified that the test did what it said it did: it tested for CYP450. But the FDA didn't require that the manufacturer show any evidence of the clinical usefulness of the test. As a consequence other companies are making these claims, and the FDA doesn't really have the stick to beat them up with.

What should the FDA do?
In the ideal scenario, genetic tests that are linked to drug selection or dosing would be under the purview of the FDA. That's one recommendation. The second is that there be more government attention to the claims that are being made about genetic tests and that the government actually take action against those who make false and misleading claims. At the moment they're not doing that. The FTC could step in. It has authority over all consumer product advertising claims. But to date the FTC has not taken any enforcement action against genetic test manufacturers or laboratories.