Tests Show AZT May Help Treat AIDS in Fetuses
Research with mice indicates that it may be possible to treat fetuses infected with the AIDS virus in the womb, a preliminary finding that scientists said could lead to decreased symptoms and prolonged life for the youngest victims of the deadly disease.
Researchers said Thursday that they infected mice in the womb with a retrovirus distantly related to the one that causes AIDS and were able to delay nervous system symptoms of the resulting disease with an antiviral drug.
Treating pregnant mice showed that the drug, AZT, crossed the placenta to reach the infected fetuses and delayed damage by the virus to the brain and central nervous system, they said.
AZT is the only drug approved for relieving symptoms of AIDS in humans.
Infected mice treated shortly after birth also showed benefits from antiviral treatment, although not as great as when therapy started in the womb, they added.
“These results are evidence for effective antiviral treatment during gestation and in the perinatal period and are of potential significance for the management of maternal transmission of the acquired immune deficiency syndrome virus,” they said in a report being published in today’s issue of the journal Science.
Dosage Important
Drs. Arlene Sharpe and Rudolf Jaenisch of the Whitehead Institute for Biomedical Research in Cambridge, Mass., and Dr. Ruth Ruprecht of Boston’s Dana-Farber Cancer Institute said also that the beneficial effects depended on the dosage.
“We have shown that AZT dramatically alters the onset and course of retrovirus-induced neurologic disease in a dose-dependent manner,” they said.
Jaenisch said AZT is a toxic drug and may not be the best one for treating prenatal cases of retroviral diseases such as AIDS. But the mouse research indicates that such early drug treatment is possible, he said, and the animal model developed at Whitehead could be a good one to screen new drugs.
Ruprecht said the mouse virus usually leads to hind-end paralysis and death in rodents within three weeks of birth. However, she said, when AZT was given to nursing mothers and their offspring, paralysis was delayed for months and the baby mice lived for five months or longer.
AZT has not been tested on pregnant women and such research would have to weigh the potential benefits against the toxicity of the drug, said Dr. Samuel Broder of the National Institutes of Health, who heads the government’s program for evaluating new AIDS drugs.
