News Release

Results Cause Modification In Children's AIDS Drug Trial

Peer-Reviewed Publication

University of North Carolina at Chapel Hill

By DAVID WILLIAMSON
UNC-CH News Services

(Embargoed) CHAPEL HILL -- Researchers at 28 U.S. medical centers have sharply modified a National Institute of Allergy and Infectious Diseases-sponsored study of drugs for combating AIDS in children because young patients in two of the study's three groups clearly fared better than those in the third.

The results confirm the value of protease inhibitors in treating HIV, the virus that causes AIDS, the researchers say. Study co-chair Dr. Sharon Nachman of the State University of New York at Stony Brook announced the change Monday (Sept. 29) at the 37th Interscience Conference on Antimicrobial Agents and Chemotherapy in Toronto.

Pediatric AIDS Clinical Trials Group trial 338 is a randomized, open study that began evaluating three different combinations of drugs, both for changes in the amount of AIDS virus in the children's blood and for safety and tolerance, according to Dr. Susan Fiscus, associate professor of microbiology at the University of North Carolina at Chapel Hill School of Medicine.

Fiscus directs UNC-CH's Retrovirology Laboratory, where all the blood analyses took place. Patients in the study, which began in late January, included 298 clinically stable HIV-infected children aged 24 months to 17 years. The first group was given the drugs ZDV and 3TC, the second group received d4T and ritonavir, which is a new protease inhibitor, and the third group received ZDV, 3TC and ritonavir.

"It was clear from a study called ACTG 320 that began earlier in adults that ZDV and 3TC plus a protease inhibitor known as indinivir were superior, at least in adults, to just ZDV and 3TC alone," Fiscus said. "For that reason, both researchers and parents wanted to follow the results closely to make sure children not getting the protease inhibitor were not being denied the best available treatment.

"An external review committee did an interim analysis of the first 45 patients to reach week 12 of the study. We had a rule that if there were medical or statistically significant differences in how the children were doing, we would act immediately for the children receiving the less beneficial regimen."

Because RNA data on more than 100 additional patients were going to be available within one week, the review committee extended the analysis to include 162 of the 298 patients.

None of the children in the three groups were known to have become more sick during the study, Fiscus said, but the number of CD4 T cells increased more in the two groups receiving the protease inhibitor ritonavir than in the group not receiving it. The AIDS virus kills such cells, which are a mainstay of the body's immune defense system.

"Also, in the two arms containing the protease inhibitor, significantly more children showed undetectable levels of the AIDS virus," she said. "These findings are consistent with studies in adults showing the dramatic effectiveness of protease inhibitors in lowering viral loads."

The research will continue to compare the two more effective treatments. Parents whose children were in the ZDV and 3TC arm and did not substantially reduce the amount of virus in their blood can enroll in a new investigation including the protease inhibitor.

Protease inhibitors work by preventing protease enzymes from cutting up proteins needed to form viruses, Fiscus said. The envelope or outer coating of the virus still develops, but the core cannot, and therefore the resulting virus is not infectious.

Dr. Andrew Wiznia of Bronx-Lebanon Hospital Center in New York City also co-chairs the study. Abbott Laboratories produces ritonavir, Glaxo-Wellcome manufactures ZDV and 3TC -- also known, respectively, as zidovudine and lamivudine -- and Bristol-Meyers Squibb makes d4T, or stavudine.

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Note: Fiscus, who is not attending the Toronto meeting, can be reached at (919) 966-6872. Nachman's number is (516) 444-7692.
Contact: David Williamson


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