OHSU Researchers Study Promising New HIV Therapy

10/30/02    Portland, Ore.

Investigational drug offers hope to patients who fail conventional therapies

Researchers at Oregon Health & Science University are testing Enfuvirtide, or T-20, one of a new class of experimental drugs for the treatment of Human Immunodeficiency Virus (HIV). The compound, which subjects administer through injection much like insulin, seems to offer significant improvement in those patients with forms of the virus currently resistant to available HIV drugs.

"I had a high level of HIV virus in my system and was never able to knock the virus very low," said Fred Schaich, study participant and AIDS activist. At the time he entered the study, Schaich had lost weight and suffered from neuropathy in his feet ‹ pain so severe it was sometimes difficult to walk. "It took a long time, but this medication seems to have worked so far."

"This is one of the first times an Oregon site has been chosen to participate in an early investigational HIV study," said Mary O¹Hearn, M.D., assistant professor of medicine (general internal medicine and geriatrics) in the OHSU School of Medicine, and principal investigator of the study. She noted that OHSU has one of the largest number of study participants, and that there are more than a thousand HIV-infected patients in the Portland metropolitan area alone. "We hope the trial will open doors for other important studies as well."

Unlike current HIV drugs, T-20 affects the virus in an unprecedented way. Termed an "entry inhibitor," the investigational drug prevents HIV from entering the subject¹s immune cells. In contrast, all three currently approved classes of HIV drugs interfere with the viral process after HIV has already entered the cell walls.

All OHSU subjects suffer from resistant strains of HIV that have made their infection difficult to control with currently available antiviral medications, such as protease inhibitors. Most have had one or more serious infections and abnormally low body weight. They are also at high risk for life-threatening complications.

Subjects were initially divided into two groups. One group received a combination of only currently approved medications, all oral drugs. The other group received a similar combination with the addition of T-20.

"Frankly, I was not optimistic we would be able to find anything that helped as much as we liked," said O¹ Hearn. "Subjects with highly resistant virus would look at others with HIV and say, ŒThese folks are doing great on their medications, why can¹t I experience a good response?¹

Instead, it has been extraordinarily gratifying to tell them that we have a new drug your disease has never been exposed to, so you can¹t be resistant, and we¹re hopeful we can get your virus completely suppressed. The results so far have been extremely gratifying."

By 24 weeks, both groups experienced mean reductions in their viral levels. However, those in the T-20 group experienced reductions twice as great. Subjects who did not respond to the drug regimen without T-20 were switched over to the T-20 group with the hope that their deteriorating health would improve. To date, they have experienced the same positive results as the test group.

This preliminary data was presented at the 14th International AIDS conference in Barcelona this past summer. Forty-eight week data on the study should soon be available. This final data will be critical to assessing whether T-20 will in fact be useful as long-term therapy for HIV. The U.S. Food and Drug Administration has granted fast-track status to the drug, and T-20 may be available as early as next year.

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