Several drugs being tested on patients with acquired immune deficiency syndrome have shown promise in combating the deadly infection, scientists have told an international meeting on AIDS.
"These early results give us some reason for optimism, but the drugs still need to be subjected to controlled trials before they enter general clinical use," said Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases.
The drugs are aimed against viruses called LAV, HTLV-III and ARV. Scientists confirmed last year that these agents are directly responsible for the destruction of immune cells that is an AIDS hallmark.
Dr. Martin B. Hirsch, an associate professor of medicine at the Massachusetts General Hospital in Boston, today described results with four such drugs. They include:
*Suramin, which has been used for years to treat tropical parasitic diseases. "Very preliminary evidence from the National Institutes of Health shows that it may inhibit the growth of the virus in AIDS patients," Hirsch said.
* APA-23, a new drug being used at the Institut Pasteur in Paris. It "has shown in some patients a reduction in LAV replication," he said.
* Alpha-interferon, an antiviral compound that inhibits HTLV-III growth. Two clinical trials on it are under way.
* Phosphoformate, initially used to treat herpes virus infections. Tests show it to be "a very potent inhibitor of HTLV-III," he said.
Even if one or more of the drugs is effective in halting growth of the AIDS virus, a second type of treatment will be needed to cure the disease, said Dr. Jean-Claude Chermann of the Institut Pasteur. "It will also be necessary to repair the immune system that the virus has destroyed," he said.
Extensive immune-system destruction allows development of severe infections and cancers found in AIDS patients.
The most promising drug for repairing the immune system is the natural substance, Interleukin-2, which in early tests caused "a marked increase" in a crucial type of immune cell, said Dr. Clifford H. Lane of the National Institutes of Health.
High doses of Interleukin-2 were used to treat four AIDS patients who have a type of cancer common in AIDS. In three of the patients, the cancer partially regressed, he said.