Getting personal: Genetic testing and custom-tailored drug treatments promise a sea change in pharmacy practice

September 18, 2006

Genetic testing and custom-tailored drug treatments promise a sea change in pharmacy practice

Imagine yourself entering the pediatrician's office, child in infant seat hoisted on your hip, papers in hand. You walk over a ripped children's book and step around a lethargic child lying on the floor as you make your way to the front desk. You remember that next week you'll be back in this office so your daughter can receive her second batch of immunizations. But today's visit is different. The secretary takes your information and insurance card and asks you a question, "Has your child been tested before?" You reply that she has not. "Well, this is her first genetic test then, right?" As you nod your head, you begin to realize the impact the results will have on your newborn. From now on, you (and eventually she) will know her tendencies to develop illnesses and disease, the way in which she will metabolize medications, and her odds to remain healthy throughout her lifetime. For a minute you feel overwhelmed with the thought of knowing all that. But, you ask yourself, what parent wouldn't want access to all the information that could help keep her child healthy? With that, you take a seat and wait.

While personalized genomics, the sequencing of an individual's entire genome, is currently too expensive and time-consuming to do routinely, there are already multiple steps being taken to drive down the costs and time required to do just that. Eventually, genome decoding could become a routine medical test performed at birth.

Sitting on the edge of this impending medical revolution are pharmacists-once again poised as gatekeepers-the key connection between the sick patient and the most appropriate drug therapy. Pharmacists will need to learn all they can about genetic testing and interpreting the results. They will require education and training on how to use the genotypic data to subsequently choose the best drug for that patient. As in pediatrics, where one size never fits all, each patient will be a special one. All the signs say this trend to personalized medicine is a big one.

No guess genes

Traditionally, physicians prescribe a medication with the hope that it will do the trick. The trial-and-error approach is widely used for many classes of drugs, mainly because our clinical trial design is based on equality across the board, with drugs indicated for all adults or all children. But now we are seeing targeted medications being developed that are for specific subsets of the population. Codeveloped and comarketed right along with the newly approved drug entity will be a genetic test that will identify responders and nonresponders. One newsworthy example is the cardiac drug bucindolol.

Bucindolol, a beta-blocker, was originally studied in a large trial sponsored by the Department of Veterans Affairs and the National Heart, Lung & Blood Institute; however, the study was halted after other beta-blockers were found to be more efficacious. Researcher Stephen B. Liggett, M.D., director of the cardiopulmonary genomics program at the University of Maryland School of Medicine, and his coresearcher Michael R. Bristow, M.D., Ph.D., codirector of the University of Colorado Cardiovascular Institute, decided to test the DNA of the study participants after finding a small subset of patients who were substantially helped by bucindolol, more so than by other beta-blockers. The gene tests identified that a group of patients were, in fact, responders, with a 38% reduction in their death rate and a 36% reduction in hospitalizations.