Right Medicine, Right Patient
Date: February 28, 2010
As far as cardiologist Rhondalyn McLean is concerned, the time is now for personalized medicine.
“We’ve seen an explosion of pharmacogenetics in the last decade,” she says. “The idea of individualizing therapies—the right medicine for the right patient—is here.”
McLean is taking that idea to heart in a study looking to identify which patients with hypertension and heart failure are responding to targeted therapy. The cardiac effects of high blood pressure—arterial wall thickening, heart failure and fatal arrhythmias—are well documented. And as part of the typical treatment for hypertension and heart failure, beta blockers have carved out their niche.
“When beta blockers are added to standard therapy,” McLean says, “we’ve seen improvement in clinical outcomes, most notably a reduction in mortality.”
Yet, because individual responses to beta blocker therapy vary widely, the question has always been whether the variance is related to genetics, environment or both. People have long believed that genetics plays a large role, but the focus has typically been on racial or ethnic variation rather than individual genetic variation.
McLean, however, is focusing more on true genetic variations, or polymorphisms, that occur despite race or ethnicity. “All people have different types of polymorphisms that can be associated with better or worse outcomes,” she says.
To that end, her study is looking at cardiac remodeling in patients who sustained heart attacks and who have been undergoing standard beta blocker therapy.
So far, two specific observations are noteworthy. First, cardiac remodeling occurred in some patients, but not others. Second, McLean has identified a single polymorphism that was associated with ventricular chamber enlargement, which is seen in cardiac remodeling.
“If we had known the genetic make-up of these patients prior to starting medication,” McLean asks, “could we have prevented ventricular chamber enlargement by giving a different beta blocker?”
If genetics do in fact dictate treatment response, she says, cardiologists could actually begin to customize and tailor therapies—that very idea of pharmacogenetics. Other cardiac drug trials based on polymorphisms include ones for ACE inhibitors and an anticoagulant medication.
“We’re probably about 10 years away from true personalized medicine,” McLean says. “More investment in studies will lead to a greater understanding of how medications affect the individual and how doctors can use that to their advantage in patient care.”