By Sean Henahan, Access Excellence

VANCOUVER (July 12,'96) Researchers are happy to have hit a triple, in the form of triple therapy regimens for AIDS patients, but have yet to hit the elusive home run of a cure. This and a concern for AIDS in the developing world were the main messages at the conclusion of the XIth International AIDS Conference.

Image: HIV Protease. Click for larger images

Numerous presentations at the conference highlighted impressive results with triple combinations of powerful antiretroviral drugs. The best news to come from the conference is that patients treated with these regimens have had all measurable amounts of HIV eliminated from their blood for periods as long as 48 weeks. These patients have also seen corresponding improvements in their health.

"We've turned a page and opened a new chapter in the history of the pandemic," said Dr. Martin Schechter, co-chair of the conference. "Many things we once thought were impossible are now within the realm of the achievable."

These studies raise numerous questions. No one is sure what will happen when or if therapy is discontinued. While the treatments appear to keep HIV in check for some period of time, it also remains to be seen if resistant forms of the virus eventually develop, as happened with earlier anti-HIV drugs. So far, it appears that multiple drug regimens appear to delay the appearance of resistant forms of HIV.

Much of the success with triple therapy has been attributed to the use of a new class of antiretroviral agents called protease inhibitors. These new drugs block an enzyme, protease, crucial to the multiplication of the virus. The HIV protease (also called proteinase) enzyme is responsible for the maturation of specific polyproteins into HIV active structural proteins and essential viral enzymes, particularly reverse transcriptase.

These drugs are now being in combination with zidovudine (AZT), a different class of drug (nucleoside analog) that inhibits a different HIV enzyme, reverse transcriptase. The idea now is to hit the virus from as many angles as possible. An important question is whether to initiate therapy early or later in the course of HIV infection.

The success of these treatments also raises related questions of how to pay for long term therapy with these agents (currently more than $15,000 per year) and how to provide treatment for the majority of AIDS patients who live in the developing world. Another issue, aside from cost, is patient compliance, since these treatments require that patients take more than 20 pills a day at regularly scheduled intervals.

But researchers have yet to hit a home run, either in terms of a proven long-term cure, or a preventive vaccine. The problem of AIDS in the developing world remains a fast growing problem. Problems include poor infrastructure, limited medical resources and poor education. The United Nations estimates that 90 percent of the world's 21.8 million HIV infected people live in the developing world. Sub-Saharan Africa continues to be the worst affected area. Public health authorities are now predicting that HIV infection, already spreading like wild fire, will reach pandemic proportions in India and China.

Related information on the Internet

XIIIth International AIDS Conference

More About Protease Inhibitors

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