A controversial new study has put a cloud over one of the most spectacular successes in AIDS. The anti-HIV drug AZT, when administered to pregnant women infected with HIV, can reduce the likelihood of mother to child transmission by almost 70%. But a study in pregnant mice now suggests that, at very high doses, the drug can cause tumors in the offspring. The manufacturer of the drug, however, has evidence suggesting that AZT in prescribed doses is safe. To get to the bottom of things, the National Institutes of Health convened a group of experts in Washington, DC, which plans to issue a recommendation tomorrow morning.
The disturbing new study, led by Lucy Anderson the National Cancer Institute, shows that megadoses pregnant mice given AZT gave birth to puppies that were more likely to develop liver tumors, lung and genitourinary tract. The Anderson team found that AZT - which stops the AIDS virus to copy itself by interfering with the synthesis of viral DNA -. was incorporated into the DNA of the puppies in a variety of fabrics, they may think leads to tumors
at lower doses, however, there is no evidence of cancer risk . When researchers at Glaxo Wellcome, which makes AZT, administered pregnant mice doses similar to those given to people, they found no increased risk of tumors in the offspring. Scientists have not seen evidence that children of AZT-treated mothers have higher rates of tumors. In addition, said Jack Killen, head of the AIDS division at the National Institute of Allergy and Infectious Diseases, researchers have known since 1989 that AZT can cause cancer in mice and yet have not seen an increase tumors in adults on medication.
group meeting today heard presentations Anderson and Glaxo Wellcome researchers and is now deliberating on the data. In principle, the committee could advise the Ministry of Health and Social Services to reverse its current recommendation that pregnant women with HIV take AZT to prevent transmission to newborns. But this is unlikely. "Many people have watched this - ethicists, clinicians, basic scientists - and everyone agrees there is no basis to change the recommendation," says Killen, the panel chair Yet said. -it, "we need to supervise children carefully and thoroughly provide information to the public so that women at the decision to have him."
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