A researcher at the Stanford University School of Medicine has helped confirm the reliability of a new test for liver disease that is ushering in the long-promised era of personalized medicine based on each individual's genetic makeup.
The Stanford group was one of the five sites that helped determine that the genetic test can identify patients who are at high risk of developing cirrhosis from chronic hepatitis C infection. That means high-risk patients could be directed toward a long course of expensive, debilitating drug therapy, while low-risk patients might be better off delaying treatment.
"Management of cirrhosis patients is challenging," said Ramsey Cheung, MD, associate professor of medicine at the school and chief of hepatology at the Palo Alto Veterans Affairs Health Care System, who led the Stanford arm of the study. "This test is the first of its kind to use the genetic makeup of each patient to determine who is likely to develop cirrhosis. High-risk patients should be targeted for early treatment."
The test looks at variations of seven genes, and was developed by Celera, headquartered in Rockville, Md.
Cheung is the senior author of the study, which will be published in the April 27 advance online issue of the journal Hepatology. Cheung is a paid consultant for Celera, which also funded the study.
"Current therapy for hepatitis C unfortunately is very expensive, has multiple side effects and a suboptimal response rate for most patients," said Cheung. Treatment includes weekly injections of alpha interferon along with the drug ribavirin, which can cost more than $30,000 per year and can cause flu-like symptoms, nausea, depression and other side effects. And only half of patients undergoing this therapy will be cured of the infection.
Nearly 4 million Americans are infected with the hepatitis C virus, of which nearly 80 percent have a chronic infection, according to the American Liver Foundation. Chronic infection can lead to the severe scarring known as cirrhosis, which in turn may result in liver cancer or liver failure. Hepatitis C infection is the most common reason people need a liver transplant in the United States and is responsible for between 8,000 and 10,000 U.S. deaths annually.
But in the majority of people chronically infected with hepatitis C, the virus causes either no symptoms or vague, nonspecific ones. In around one-third of people chronically infected with the virus, the disease progression is slow and they may never develop cirrhosis, even after decades of infection.
The dilemma physicians face, explained Cheung, is deciding who to treat and who can wait for better therapies to come along. The key is being able to determine which patients are likely to see the infection progress to cirrhosis. Doctors consider such factors as age, gender and alcohol consumption to predict such risk, but because of individual variability, these factors don't yield a very accurate prediction. A liver biopsy can indicate the amount of damage to the liver up until the time of the biopsy, but can't reveal how much future damage will occur.