If personalized medicine’s promise isn’t easily understood, Dr. Kristin Newby can readily explain it through her clinical practice.
The cardiologist at the Duke University Medical Center in Durham, North Carolina routinely sees patients who have had a heart attack or are at risk for one. But some of them had heart attacks without showing any heart risks. Others show risks but haven’t had heart attacks. For each patient, Newby must determine how to treat and how aggressively to treat.
“I think that’s where biomarkers come in,” she said.
Biomarkers, short for biological markers, are substances or characteristics that can be measured to guide a clinician in making diagnostic and treatment decisions. Technologies that can identify biomarkers for particular diseases hold the keys to new doors of opportunity for personalized medicine that could lead doctors to tailor their treatments to individual patients. But for all their promise, many such technologies have yet to be realized. Newby has few cardiac biomarker tests available to her; most such tests remain in research and development. That’s the case for a lot of tests still being researched for other diseases.
Personalized medicine was touted as the future of medicine at a recent Duke University symposium on the topic. But that promise was tempered with a more sober reality on Wednesday in Research Triangle Park, North Carolina during a CED Biotech Forum panel on personalized medicine. Dr. David Ransohoff, a professor of medicine and epidemiology at the University of North Carolina’s School of Medicine, said that for all of personalized medicine’s promise, identifying biomarkers and developing tests for them has proven to be a difficult task.
“Mother nature is nasty and mean,” he said. “She guards her secrets really well.”
RTP company Metabolon has found some success developing biomarker diagnostics. Metabolon has developed and commercialized a test for type 2 diabetes. The company is also developing a prostate cancer test. CEO John Ryals said that the company is often asked if it can develop diagnostics for Alzheimer’s disease and Lou Gehrig’s disease. But Ryals said some indications pose greater challenges than others. In Alzheimer’s disease, for example, there is no “gold standard” of measurement. Many elderly people have some form of cognitive impairment that is not necessarily Alzheimer’s.
A test that gives earlier detection of disease can mean earlier intervention. That intervention is not necessarily a medical treatment. Jeff Shuster, general manager of The Biomarker Factory, a company that funds diagnostics personalized medicine research, said earlier Alzheimer’s detection could help patients and their families plan ahead. But he added that any diagnostic must be balanced with the knowledge that no test is 100 percent accurate and even correct results may be false positive readings. That result would be unwelcome to patients.
“We always ask, ‘What’s the cost of a false positive or a false negative to that patient,’” he said.
But even the latest advances in biomarker technologies don’t necessarily lead to an immediate path to clinical applications. Expression Analysis provides research services to pharmaceutical and biotech companies and others doing genomics research. But Pat Hurban, the Durham firm’s vice president of R&D, said his company’s technologies are too expensive for clinical applications. In the current healthcare market, affordability will be key to the commercial viability of any test, Ryals said. A $100 test could be useful to a patient and affordable to a payer. But a $5,000 test would be deemed too expensive no matter what information it yields.
Newby said the value of new tests will be not only in the treatments decisions that they inform, but also the treatments that they avoid. If a test suggests that a patient does not need to go to a catheterization lab, that helps clinicians align resources with health risks. But even if tests don’t make their way into clinical use, they do have research value. Newby, who has led multiple clinical trials at the Duke Clinical Research Institute, said that tests can be used to identify patients for clinical trials of experimental drugs. New tests will also be important in helping clinicians in their drug-prescribing decisions.
“Companion diagnostics is a huge place where biomarkers have a role,” Newby said.
[Photo from stock.xchng user Miguel Saavedra]