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rfmcdonaldIt's worth noting that AZT, the first commercially marketed drug to attack HIV, itself can trace its origins to research into cancer drugs, so this news item isn't that surprising.
It will be quite risky, though.
The 30-year-long search for a cure for AIDS, the world’s deadliest viral infection, may get a renewed boost from an unlikely source: a little-used Merck & Co. cancer drug.
Researchers at the University of North Carolina in Chapel Hill plan to test Merck’s drug, Zolinza, next year in about 20 people infected with HIV, the AIDS virus. The goal is to determine if Zolinza, or a medicine like it, can force HIV out of cells where it can reside, concealed from attack by potent antiviral treatments, said David Margolis, a professor of medicine who’s leading the research.
While AIDS drug cocktails can eliminate more than 99 percent of virus from an infected person, the treatment isn’t a cure because a remnant of the virus remains hidden in certain cells. For years, scientists have sought a simple way to drive the remaining virus into the bloodstream where the drugs can clear them from the body. Zolinza, approved in 2006 for use against a rare type of blood cancer, may work by blocking an enzyme that helps the virus avoid detection.
“It’s really all about trying to move the field ahead,” Margolis said in a telephone interview. “We don’t expect to cure anybody, but we expect to really show whether it can work the way we think it does in people -- or not.”
Zolinza earned Whitehouse Station, New Jersey-based Merck $15 million in 2008, the last year it disclosed sales of the drug, for treating a malignancy of white blood cells that affects the skin. In a laboratory test published last year, Margolis used the medicine to coax HIV out of hiding in cells taken from infected patients. Now he wants to replicate the result inside the body. Success would show he’s on the right track to finding a cure.
“There is a good chance that it will cause some activation of latently infected cells,” said Robert Siliciano, a professor of medicine at Johns Hopkins University in Baltimore who first identified the cells in which HIV hides out, and isn’t involved in the Zolinza trial. “Nobody knows if it will work, but it’s important to try.”
It will be quite risky, though.
Zolinza targets an enzyme called histone deacetylase, or HDAC, that helps HIV go to sleep in cells by interfering with its ability to replicate. By blocking HDAC, Zolinza would reactivate the virus, kickstarting reproduction.
From there, nature would take its course: HIV would exit and kill its host cell, and enter the bloodstream in search of new cells to infect. Anti-AIDS drugs would prevent it from doing so, and with nowhere left to go, the virus would die after several hours.
Margolis and his colleagues plan to give about 20 patients a few doses of Zolinza, then measure whether it’s had any effect on the amount of virus the immune cells are producing. That will tell them whether they’ve succeeded in disturbing the reservoir.
Zolinza, also known as SAHA, may not be suitable as a cure for AIDS because of its potential to cause genetic mutations that lead to cancer, Margolis said. The U.S. Food and Drug Administration accepts that risk when the drug is being used in patients who already have cancer. It probably won’t tolerate the risk for use in other diseases, Margolis said.
The FDA has approved the trial “because we will so severely limit the exposure to SAHA that the risk of inducing cancer is felt to be negligible, like getting on a plane and taking a flight to New York, or lying on the beach and getting a tan,” he said.
