By DAVID WILLIAMSON
UNC-CH News Services
CHAPEL HILL -- People infected with HIV, the virus that causes AIDS, and medical scientists received disappointing news Thursday evening (Dec. 5) as a national study showed that a vaccine will not stop the virus from reproducing. Neither will the vaccine slow destruction of infected people's immune systems.
"When this study began in 1993, we and many others had high hopes that this vaccine, which was produced by Genentech Inc., would halt progression of HIV in people who test positive and the illness," said Dr. Joseph J. Eron Jr., assistant professor of medicine at the University of North Carolina at Chapel Hill School of Medicine. "It turns out that does not happen."
A report on the findings appears in the Friday (Dec. 6) issue of The Lancet, a British medical journal. Authors include Eron, principal investigator for the multicenter project, and Dr. Mark A. Ashby, Marlene Chernow and Dr. Thomas Twaddell, all of Genentech.
Researchers at UNC-CH, the universities of California at Los Angeles and San Francisco, Cornell, and Georgetown universities and other AIDS treatment facilities across the United States evaluated 568 volunteers infected with HIV, but who were otherwise healthy. Every month for six months and then once every other month throughout the study, they gave a vaccine known as MNrgp120 to 287 patients and an inactive substance, or placebo, to 281 others.
At the study's beginning, all patients had CD4 cell counts of over 600 per milliliter. CD4 cells -- key components of the body's immune system -- are the chief targets of the AIDS virus and decline in number as the illness progresses..
At the end of treatment and follow-up, researchers found no significant differences in CD4 counts between patients who received the vaccine and those who received the inactive compound. The immune systems of both groups continued to decline, and levels of virus in both groups increased.
"Patients treated with this particular vaccine, which appeared to be one of the most promising, received absolutely no benefit," Eron said. "In addition, unlike previous studies, this one was large and well-controlled enough that we can say with confidence that there was no significant benefit."
Other vaccines may be developed later that work better, but would have to very different from the one given, the physician said. He praised Genentech staff for working hard to publish the information, which he said usually does not happen when results are disappointing.
In an accompanying editorial, Dr. Barton Haynes of Duke University called the new study well designed and controlled.
"Carefully performed work such as the study of Eron and others showing that a drug or strategy does not work is an important as a positive study, in that it shows that attention can now be turned to other strategies," Haynes wrote.
Genentech supported the research, which was a randomized, double-blind, placebo-controlled trial. In such studies, designed to reduce or eliminate bias, scientists do not know which patients receive which substance until the investigation concludes, and patients are randomly assigned to treatment and control groups.
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Note: Eron can be reached at (919) 966-2536. His pager number is (919) 216-0560.
Contact: David Williamson