SAFETY OF COMMON AIDS DRUG QUESTIONED IN SOUTH AFRICA Divergent views on the risks and benefits of AZT

By Rachel Swarns

New York Times 25 Nov. 1999

Johannesburg -- Stirring a furor among doctors and researchers who treat patients infected with the virus that causes AIDS, government officials here have been questioning the safety of the standard anti-AIDS drug AZT, saying they suspect it may be too dangerous to justify its use. In a speech last week to the National Assembly, Health Minister Manto Tshabalala-Msimang said that the drug might be toxic and might cause some forms of cancer. "This is a very serious finding," she said in a statement.

Her comments echoed the concerns of President Thabo Mbeki, who last month requested a safety review of the drug, which has been approved for use by the Food and Drug Administration in the United States and by the World Health Organization.

"There exists a large volume of scientific literature alleging that, among other things, the toxicity of this drug is such that it is in fact a danger to health," Mbeki said in a speech to provincial leaders. "These are matters of great concern to the government as it would be irresponsible for us not to heed the dire warnings which medical researchers have been making."

The statements have touched off a flurry of protests from doctors and others concerned about AIDS in this country, which has one of the world's highest rates of infection with H.I.V., the virus that causes the disease.

AIDS experts say concerns about AZT, particularly for children, have been raised in the United States. One study found that pregnant mice treated with AZT gave birth to babies with tumors. The relevance for humans is unknown.

But after reviewing the mouse studies and others like it, the National Institutes of Health determined in 1997 that the benefits of the drug far outweigh the potential side effects.

AZT is used to treat people infected with H.I.V. and has been particularly effective in reducing the transmission of the virus from pregnant women to their fetuses. One two-year study found that a short course of AZT treatment administered to women who did not breast-feed their babies reduced transmission of the virus by 50 percent.

"There is toxicity, but this is not a sweet, this is a drug," said Dr. Joseph Perriens, who heads the care and support program of the United Nations AIDS program in Geneva.

"To combat a fatal disease, it is perfectly acceptable to use drugs slightly more toxic than an aspirin," he said. "AZT is a valuable therapeutic drug. Its efficacy is a very important consideration and needs to be taken into account."

Doctors, advocates for AIDS patients and executives of the company that produces AZT, Glaxo Wellcome, have urged the government to review the scientific literature. The government, which has vowed to battle AIDS aggressively, has promised that it will make such a review.

But Ms. Tshabalala-Msimang said that even if AZT proves to be safe, it is too expensive to distribute. An estimated 3.6 million of South Africa's 44 million people are infected with H.I.V. And treating all those people with AZT would cost the government 10 times what it currently spends on health care, she said.

She said the government is also looking into a new drug that researchers say is less costly and more effective than AZT in reducing mother-to- child transmission. The cost for two doses of the drug, nevirapine, is about $4, compared with $268 for the AZT regimen used in developing countries and $815 for the much longer and more complicated course used in the United States and other developed countries.