February 14, 1997

VUMC testing new vaccine designed to fight HIV virus

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Dr. David Haas and Research Coordinator Victoria Harris discuss Vanderbilt's clinical trial of a new HIV vaccine.

VUMC testing new vaccine designed to fight HIV virus

Vanderbilt University Medical Center investigators are testing a new drug that bolsters the body's immune system to help fight the HIV virus.

The new drug, Remune, is currently the subject of a clinical trial being conducted at VUMC and several other institutions across the country.

Used with protease inhibitors, which interfere with the HIV cell's ability to replicate the virus, the drug is designed to stimulate the immune system's response to the HIV virus.

Together these drugs execute a two-pronged attack on the HIV virus.

"This is a therapeutic vaccine," said Dr. David W. Haas, associate professor of Medicine and director of the HIV/AIDS Clinical Trials. "The drug may give an important second punch to the cycle of HIV infection."

"During the early days of the AIDS epidemic this was considered almost entirely an immune disease and all of our efforts were aimed at dealing with the immune complications . Then as we learned more and more about the disease and better drugs became available our focus has been more on viral replication and how to stop it. Now a major part of the emphasis has shifted back to finding ways to fight the disease on an immunologic level," said Haas.

Remune works by stimulating the immune system's T cells to attack HIV infected cells. It is designed to take advantage of the amount of virus already present in a person to enhance the body's natural defense mechanisms.

Remune consists of two basic components. The first is killed HIV cells that have been stripped of their outermost protein, gp120. The inactivated virus still contains the proteins which are most widely recognized by the immune system.

The second part component is a potent stimulator of immune cells, commonly called an adjuvant. The adjuvant enhances the immune system's response to the viral proteins in Remune.

By seeing these HIV proteins often enough, it is hoped that the body's CD4 T cells, which direct the actions of other immune cells, can begin to find ways to destroy the virus in more efficient ways.

"Most of the focus in drug development in AIDS has been to find a way to block the virus's ability to multiply in a person's body," said Haas.

"This study is based on the idea that, at the same time you are taking anti-viral drugs to decrease viral replication, adding to that a therapy that may stimulate the body's immune system at the same time may be a great thing."

To be eligible for the trial a person must be HIV-positive, have a T-cell count between 300 and 549 and be on a stable anti-retroviral therapy for at least 30 days before the screening.

"There are 60 sites across the country doing this study and we are hoping to enroll at least 50 of the 2,000 that will volunteer nationwide," said Victoria L. Harris, HIV/AIDS Research Coordinator.

This type of immune response enhancing therapy has been around for a number of years. Earlier studies, however, were not lengthy enough to see the results that scientists hope these drugs will show, said Haas. As a result, this study will go on for three years, which is long for a clinical trial, said Harris.

A small stipend will be given each time the participant gets an injection of the drug, which is administered every three months.

"We realize that many people live far away and may find it difficult to drive all this way every three months, which is why there is a stipend," said Harris.

Anyone interested in becoming a part of the study or who would like more details should contact Victoria Harris at 936-1164 for more information.