San Francisco Chronicle - Thursday June 8, 1989
David Perlman, Chronicle Science Editor

Although progress is slow and the basic science to understand how the virus attacks the human immune system is a profound challenge, Dr. Samuel Broder offered an unusually optimistic view of where the AIDS battle stands today.

He gave his report to a crowded audience at the fifth International AIDS Conference in Montreal, where by now more than 11,800 delegates from 130 nations have registered for 204 separate sessions on science, politics, human rights and the lethal epidemic's economic and social costs.

AZT, the drug that prevents the AIDS virus from reproducing inside the cells it infects, is now being used by some 20,000 Americans who either have the disease or are infected with the virus known as HIV.

The drug is now extending the life-span by 18 months or more for nearly two-thirds of those who use it. In 1982, before AZT was available, only 30 percent of all AIDS patients had a chance of living as long as 18 months.

"In the early '50s and '60s there were many people who said there would be no progress against childhood leukemias," Broder said as he recalled his own cancer research. "But thanks to new therapies that were developed, those people were as wrong as those today who say we won't make progress against AIDS." AZT STILL VALUABLE

Even though many people develop resistance to AZT and for others high doses of the drug prove toxic, it is still extremely valuable, Broder said. New combinations of AZT with other drugs are showing highly promising results in early trials, he said.

Broder specifically cited two drugs, both of which also act to block an essential enzyme called reverse transcriptase inside the AIDS virus and thereby prevent the virus from duplicating itself.

One is known as DDC, which stands for dideoxycytidine and is also a powerful anti-viral compound. Although it can cause severe nerve damage in high doses, Broder suggested it could be used to alternate weekly with AZT in many patients.

DDC, he said, causes a dramatic increase in the body's T-4 cells, which are key immune system cells attacked by the AIDS virus in early stages of infection. Tests have also shown that DDC causes a "precipitous drop" in protein molecules called P-24, and their disappearance in cultured cells indicates that the AIDS virus itself is disappearing.

Another, closely related drug known as DDI, or dideoxyinosine, is also showing "statistically significant" anti-viral activity, Broder said. It can easily be given in pill form - perhaps as infrequently as once a day, he said. The drug may also turn out to work in patients who have developed resistance to AZT, he said. USES THE WORD "CURE'

Blocking the activity of the AIDS virus with drugs that prevent viral reproduction, Broder said, is the "foundation stone" of the new therapies -and he was bold enough to say it could lead to a "cure."

Broder also reported new research with the genetically engineered protein called CD-4, a compound that duplicates the receptor molecules on the surface of T-4 cells where invading AIDS viruses attach themselves.

CD-4 alone may not prove to be the ideal "decoy" drug that lures invading AIDS viruses away from the T-4 cells, Broder said. But scientists at Genentech, a South San Francisco biotechnology company, have learned to combine CD-4 with substances known as immunoglobulins to create genetically engineered antibodies that could prove both long-lasting and effective in killing the viruses, he said.

Always watch for outdated information. This article first appeared in 1989. This material is designed to support, not replace, the relationship that exists between you and your doctor.

AEGiS presents published material, reprinted with permission and neither endorses nor opposes any material. All information contained on this website, including information relating to health conditions, products, and treatments, is for informational purposes only. It is often presented in summary or aggregate form. It is not meant to be a substitute for the advice provided by your own physician or other medical professionals. Always discuss treatment options with a doctor who specializes in treating HIV.

Copyright ©1980, 1989. AEGiS. All materials appearing on AEGiS are protected by copyright as a collective work or compilation under U.S. copyright and other laws and are the property of AEGiS, or the party credited as the provider of the content. .