In another example of the potential of personalized medicine, a study released Thursday showed that a genetic test can help some heart-transplant patients avoid frequent biopsies used to determine whether they are rejecting the organ.
Researchers reported Thursday that a gene test marketed by XDx Inc., of Brisbane, Calif., a closely held molecular diagnostics company, was just as effective as routine biopsies in helping patients avoid serious complications of heart-transplant surgery, including death, a second transplant or heart-failure symptoms that are often a result of organ rejection.
The study, involving 602 heart-transplant patients, was presented at a meeting of the International Society for Heart & Lung Transplantation in Chicago and published online by the New England Journal of Medicine.
Rejection of a donated heart is among the most serious complications of a transplant operation. Doctors typically take regular biopsies to obtain pieces of heart muscle to monitor patients for rejection before any symptoms arise. For years, they have been looking for a test that could be a safe and effective alternative to the often painful procedure.
The new study was conducted among patients considered at low risk of rejection at least six months after they underwent a heart-transplant operation. After 19 months of follow-up, 14.5 percent of patients monitored with the gene test and 15.3 percent of those followed with routine biopsies died or suffered another major complication from the procedure.
"You're not going to harm patients by reducing the number of biopsies," said Michael X. Pham, a Stanford University Medical Center cardiologist and lead author of the study.
Limitations of the study included its enrollment of low-risk patients.
The gene test, called Allomap, has been on the market since 2005 and has been used on 7,000 patients, XDx said. It costs about $3,000 while biopsies typically cost $4,000 to $5,000, the company said.
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