Insurance reimbursement also is improving, Dr. Mrazek said. "As insurance companies become aware there is a cost benefit to this, [because] you can avoid unsuccessful medication trials by doing a one-time and not-astronomically-expensive test, insurance companies will learn it’s in their best interest to approve these, and many do already.
"It’s very rapidly evolving. What we called pharmacogenomic testing a few years ago and what we call it now is different," Dr. Mrazek said. He predicted use of this testing will increase exponentially as the cost comes down and as the algorithms used by laboratories to interpret the results become more sophisticated. In the meantime, "it’s a tool people can choose to use or not to use. But once you get used to being more accurate [with prescribing], it’s hard for most people to go back and just take the dart and throw it at the board again."
It is important to choose a laboratory that provides easy-to-understand reports, Dr. Mrazek added. "Some of the reference labs will send you a report that takes a biochemist to understand what the results mean."
"There are many genes now we are starting to test," Dr. Mrazek said. The easiest genes to understand are the ones that produce these metabolic enzymes. "We’re also learning about target genes that code for the receptors and the transporters in the body, and patients can have problems with those as well."
The future will be more about gene sequencing in a particular patient versus looking at a few key variants, Dr. Mrazek predicted. "When we do this sequencing, instead of just genotyping, we are going to discover lots more of the relevant variation in the genes. It’s like a microscope. [Currently] we are looking at it out of focus, but it’s still better than no microscope. With sequencing, all kinds of things we can’t see now will come into focus. The image will get sharper, the resolution will get better."
Dr. Mrazek invented a patented algorithm for interpretation of pharmacogenomic test results. The Mayo Clinic licenses the algorithm to companies, and Dr. Mrazek said he might receive a financial benefit from this patent in the future.