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The Human Face Of Pharma

June 19, 2006

Prediction By Genetics

FDA official hopes greater use of genetics in deciding treatments will yield better outcomes

Rachel Petkewich

FDA Photo

Robert Temple

"As everybody's noticed, life expectancy has gone through the roof," says Robert Temple, the director for medical policy at the Food & Drug Administration's Center for Drug Evaluation & Research. He attributes that longevity to the use of beneficial cardiovascular pharmaceuticals, and this view is supported by persuasive data from large studies.

Temple says a major hope is to become better able to predict risk, and perhaps response, by looking at biomarkers, which are measurable substances, such as proteins or metabolites, whose presence or concentration varies in response to a drug.

Researchers know now that high cholesterol levels or high blood pressures predict a high rate of cardiac and vascular events, Temple says, but within seemingly similar groups, wide differences in risk and response exist. The next frontier in those studies is a better understanding of genetics and blood factors that may play a key role in defining risks or predicting responses to treatments, he says.

In general, development of cardiovascular drugs has benefited from the ability to conduct placebo studies. These studies are possible because cardiovascular patients don't feel sick and so are willing to participate in long-term placebo studies, explains Temple, who is trained as a medical doctor. On the other hand, people with painful arthritis, for example, are less willing to go without treatment, and for their diseases, discovering the difference between treatment and no treatment is more difficult, he says.

In certain areas, such as cardiovascular health, Temple says the main task is not to develop more drugs, but to get people to use known information to control their blood pressure and lipid levels. He adds that the main scientific question now is how low a patient's blood pressure or cholesterol should be, and that the answer is different for different people. Researchers now design clinical trials and other medical studies for particular groups of people, and results of genetic testing could help refine the studies to answer this question.

Temple cites an example of how patients who seem to be at similar risk might actually have considerably different risks. In a study that looked at the risk of having a heart attack or dying in the next 30 days among the patients in the placebo group, all the participants had been diagnosed with acute coronary syndrome—essentially, they were having chest pain that appeared cardiac in nature—had at least 70% obstruction of one coronary vessel, and had an angioplasty, a surgical repair of blood vessels.

"Those criteria would have been thought to characterize them pretty well, and the patients seemed very much alike," he says. But they differed in three blood factors. "It turns out that within those seemingly identical people, three measurements of factors from their blood turned out to be very important in identifying whether they were at high risk or less high risk." People with high levels of these factors were at much greater risk, an important thing to know in a clinical trial or during treatment.

Cancer also provides good examples of the possible benefits of genetic testing. Temple explains that DNA analysis is, in some cases, a better predictor than, for instance, what a tumor looks like under a microscope. "In other words, all the things we use to predict are sometimes not as good at predicting as this genetic characteristic of the tumor," he says.

And genetic testing would be much easier on the patient—physically, emotionally, and financially—than "trying" a treatment such as chemotherapy. Testing to predict who is at risk of recurrence is one use of biomarkers. The hope is that tumor markers will be able to predict which tumor will respond to a particular treatment, he adds.

C&EN SPECIAL ISSUE: Pharma's Road Ahead

Cover Page Thumbnail
Pharma's Road Ahead
Volume 84, Issue 25
June 19, 2006
Table Of Contents
Web Feature: The Human Face of Pharma

Seventeen individuals whose lives depend on, or whose livelihoods are affected by, the pharmaceutical industry offer unique perspectives on what pharma's future should be.