Making Medicine Personal
A number of scientists bared their genetic souls recently as part of the Personal Genome Project, a study at Harvard University Medical School. They were among the first of the eventually 100,000 volunteers who will agree to place their genetic profiles on the Internet.
Genetic profiling can provide information on what diseases may befall us. And knowledge of an individual’s genetic makeup may also help scientists figure out how to treat diseases—part of an emerging field known as personalized medicine.
As many doctors freely admit, says Julie Johnson, director of the Center of Phamacogenomics at the University of Florida (UF), prescribing medicine is “more of an art than a science.” Approved drugs work—but not 100 percent of the time, and not for 100 percent of the population. Some people have no response to certain drugs, and others experience severe side effects.
What determines whether a particular treatment is effective or leads to severe side effects is our genes, scientists believe. Personalized medicine holds the promise of tailored medical treatments based on genetic information, rather than a one-size-fits-all approach.
The UF center participated in studies on warfarin, a blood thinner prescribed for millions of Americans to prevent heart attack or clotting after a heart attack. Too little of the drug causes a risk of clotting, and too much can cause excessive bleeding. “There’s a very narrow window, and there’s a great deal of variability among patients,” says Johnson. “A lot of work in the past decade has uncovered several genes that help explain a great deal of that variability.” In 2007, the FDA cleared a genetic test for sensitivity to warfarin to help doctors prescribe the correct dosage, although the tests are not yet widely implemented.
The UF center is also focusing research on drugs prescribed for hypertension, in an attempt to find the genes that “will predict how much a person’s blood pressure will go down if they’re administered certain medicines,” says Johnson.
Speeding the Process
Part of what has contributed to the increasing interest in personalized medicine is the speed and cost of sequencing genomes. The first human genome took many years and millions of dollars to sequence. The price has already dropped into the thousands instead of millions of dollars, and it’s expected to continue to fall. The journal Science listed “faster, cheaper genome sequencing” as one of the top scientific advances in 2008.
These advances have increased the speed of research in the field. John Reed, the president and CEO of Burnham Institute for Medical Research, a center with campuses in San Diego, CA, and Orlando, FL, says that the Florida campus has engaged in major initiatives related to personalized medicine. While Burnham’s research has traditionally focused on cancer and on neurodegenerative and inflammatory diseases, the scientific team is expanding into obesity, diabetes, and metabolism research.
“We all have friends who can eat french fries every day and never gain weight, while the rest of us will have a hard time getting the belt to fit,” says Reed. “There are genetic differences in how we metabolize food—individual metabolic rates, hormone signaling—that’s all just being worked out.” Burnham is partnering with the clinical research institute at Florida Hospital, particularly the diabetes center, to engage in research on the metabolic systems of the patients there.
A related field of research involves investigating which chemicals can affect the actions of proteins, encoded by specific genes. This is a natural path to drug discovery, but it can also aid in genomic research. “A chemical probe can be used in basic research to help identify the role of a protein or a pathway, aiding in understanding the biology of a particular gene,” says Patrick Griffin, chair of Molecular Therapeutics at Scripps Florida, a campus of Scripps Research Institute headquartered in California.
The National Institutes of Health (NIH) funds four molecule-screening centers in the United States to rapidly test a library of chemicals against specific proteins. Scripps Florida operates one of the four centers.
Burnham operates a second of those NIH molecule-screening centers at both its California and Florida research centers. Currently, its screening output can tackle half a million chemicals in one day, but the new system being developed in Orlando will be able to handle as many as 2.2 million chemicals a day.
The fields of genome research and rapid drug discovery are coming together to enhance each other, says Reed. “We’ll be able to, with far more accuracy, define for whom a drug is really going to work, and to avoid a lot of trial and error that we experience when we’re confronted with a health issue.” He and other researchers in the field see a time not too far in the future when understanding individual genomes will lead to better, more effective medical treatments for everyone.