CONTACT:
Richard Puff
Albany Medical College
518-262-3421
FOR RELEASE: 7 p.m. EST September 14, 1997
ALBANY, N.Y., Sept. 14, 1997 - Albany Medical College researchers have for the first time provided data that shows that the major predictor of resistance to AIDS drugs is whether the amount of virus in a patient's body has been reduced to nondetectable limits.
"People have suggested this was true along with other factors for a long time, but there never was comparative data to prove it," said Daniel Stein, M.D., associate professor of medicine and pharmacology at Albany Medical College and director of the Albany Medical Center pharmacology studies unit.
The Albany Medical College team (Dr. Stein, George Drusano, M.D., professor of medicine and pharmacology and head of the division of clinical pharmacology, and senior virologist John Bilello, Ph.D.), and researchers from Merck Research Laboratories, West Point, Pa., presented their findings today at the 35th annual meeting of the Infectious Diseases Society of America in San Francisco.
The group analyzed data from five clinical trials involving 197 patients who received the protease inhibitor Indinavir alone and with other drugs used to treat AIDS, including AZT, ddI and 3TC.
Typically, when patients become resistant to Indinavir monotherapy, their measured virus in the circulation rapidly returns to their pretreatment concentration.
The analysis showed that among the patients who received just Indinavir, those who were able to reduce the amount of virus in them to less than detectable levels had "significantly lower risks of emergence of resistance" to the drug. When combination therapy was used, such as a combined treatment of Indinavir, AZT, and 3TC, patients had significantly longer times to resistance compared to monotherapy patients even after adjusting statistically for the increased antiviral effect of the additional drugs.
"Patients should receive combination chemotherapy regimens, if at all possible, to minimize the emergence of resistance to the protease inhibitor portion of the regimen," the researchers said in their abstract. Driving the level of virus in their patient's system "to less than detectability should be a goal of therapy for clinicians," they concluded.
Dr. Bilello added that "until potent multidrug regimens were designed which could markedly inhibit several distinct viral genes, resistance would be the major problem in long-term treatment."
"This data shows that it does not matter how much you decrease the viral load," Dr. Stein said. "Unless it reaches the point of being undetectable, your risk of ultimately failing therapy is high."
An undetectable level of HIV does not mean that the patient has eliminated the virus from their system. It merely means that the level has gone below that which can be detected by currently available methods, Dr. Stein noted.
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