DURHAM, N.C. - Detecting whether patients with HIV/AIDS are infected with even small amounts of drug-resistant forms of the virus can be done with a test developed by researchers at Duke University Medical Center.
While other tests only pick up drug-resistant strains when they represent a significant portion of the virus in a person's bloodstream, the test developed at Duke may enable doctors to more accurately predict which medicines will work for patients and which drugs will ultimately fail.
"This can be huge," said Dr. Feng Gao, a Duke HIV/AIDS researcher and co-author of the article published online Sunday in the journal Nature Methods.
So far, the test has been used for research purposes only. Duke is seeking patents that will enable it to develop a diagnostic screening for future commercial use.
A private industry backer is still needed, along with other studies that demonstrate the process helps improve treatment outcome.
Duke's new test comes amid rising evidence that HIV drug-resistance is a problem, even among patients who have never been treated with antiretroviral drugs. Studies have found that 15 percent or more of patients newly diagnosed with HIV harbor drug-resistant strains of the virus.
"A lot of questions are still unanswered, but it's an important step forward," said Dr. Peter Leone, an HIV/AIDS doctor at the University of North Carolina at Chapel Hill and medical director of the state's HIV prevention branch.
If the test pans out, Leone said, it would "improve the odds that the first course of treatment is going to be successful."
Even the less sensitive tests available now are helpful in avoiding treatment pitfalls, said Dr. Charles Hicks, a Duke infectious disease specialist who treats patients with HIV/AIDS and is co-author on the journal article.
He says a common mutant strain picked up by such tests resists one of the first-line treatments for HIV, and if patients test positive for that type of drug-resistant strain, doctors know to prescribe other medicines.
"It makes you choose a totally different treatment path," Hicks said.
Duke's test is more sensitive and detects resistant strains that make up less than 1 percent of the virus circulating in the patient's blood. With existing tests, drug-resistant HIV strains are picked up only if they make up 20 percent or more of the total virus in the patient's system.
"Even if you don't see resistance, you can't be sure that it's not really there," Hicks said. "That's a huge problem."
