March 13, 1998

Researchers test patient-friendly HIV/AIDS drug

Researchers test patient-friendly HIV/AIDS drug

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Dr. David Haas is testing a new HIV/AIDS treatment. (Photo by Donna Jones Bailey).

The Vanderbilt AIDS Clinical Trials Center is testing a new AIDS/HIV medication that could become the next weapon in the fight against the disease.

In one of the studies ‹ being conducted at 15 sites around the country ‹ the new medication, named efavirenz, has proven effective in reducing HIV levels, according to Dr. David W. Haas, associate professor of Medicine in Infectious Diseases and director of the AIDS Clinical Trials Center.

³This new drug has several potential uses in HIV therapy. One possible role would be as first-line therapy in combination with other approved drugs for people who have not previously been on treatment,² said Haas.

³Perhaps the biggest advantage to this drug, in addition to its antiretroviral effect, is that it can be given once a day. With drug adherence being such a factor in how well patients respond to therapy, the move is toward easier-to-take regimens. This will likely become the first antiretroviral drug to be approved for once-a-day usage. It¹s a major advance.²

Haas presented study findings recently at the Fifth Conference on Retroviruses and Opportunistic Infections in Chicago. Patients in the study were treated with efavirenz in combination with other popular AIDS/HIV medications AZT (zidovudine) and 3TC (lamivudine).

³Results from the first 137 volunteers enrolled have shown that patients respond very well to this combination therapy without using a protease inhibitor," Haas said. "About 90 percent of study patients have achieved an undetectable level of virus in their blood. Right now that¹s the gold standard for measuring how effective an antiretroviral agent is."

Haas says that these early study results are comparable to the results seen with other potent combination regimens. HIV patients on protease inhibitors often find it hard to manage their drug regimens. Haas says current therapies require patients take their medications at least two or three times a day, and staying on such a regimen is difficult.

³At this point, most physicians feel that for patients who have not previously been on treatment, the most important factor that determines whether they will respond optimally to therapy is how well they take all their medicines,² he said.

³For some people the number of drugs they have to take is so challenging that it¹s not surprising that they don¹t respond completely to therapy.²

Study participant Arlis Green agrees with Haas about efavirenz being easier to take.

³It¹s not hard at all, I take the medication once a day right at bedtime,² said Green, who enrolled in the study after his T-cell count began to drop.

³I¹ve been on the medication for about one year and haven¹t had any side effects at all. It brought my T-cell count right back up.²

Haas says that in a review of patients in the Middle Tennessee area who started protease inhibitors in clinical practice ‹ all of whom had been previously treated with other drugs ‹ only about 40 percent achieved an undetectable viral level in their blood. The factors contributing to the low response were most likely the patient's inability to take medicines on schedule and viral drug resistance.

In addition to its role as initial drug therapy, efavirenz may have other roles in treating AIDS/HIV patients, both in regimens with and without protease inhibitors.

³It makes sense that both protease inhibitors and efavirenz may be used in some combination,² Haas said. ³The benefits may be very great, and there are studies ongoing to look at that possibility.²

³So far there has not been a head-to-head study that looks at the effectiveness of a regimen that uses efavirenz versus a regimen that uses protease inhibitors, and we really need to look at that to see if the regimens are comparable.²

Haas says that efavirenz may also be useful as a ³salvage therapy² for patients who have been on other regimens and found them ineffective.

³There are hundreds of people in the Middle Tennessee area who have been on other therapies and didn¹t respond very well to any regimen they tried. So an important place for this drug would also be as a component of salvage therapy in combination with other treatments,² he said.

³Patients who fail with one protease inhibitor tend to fail with all protease inhibitors. If you can go to a completely new class of drugs the chance of effectiveness is greater, and efavirenz belongs to a different class of drug.²

The Vanderbilt AIDS Clinical Trials Center has a number of ongoing research projects and offers participants access to the latest antiretroviral therapies available. Patients or physicians interested in current research projects should contact Clinical Research Manager Victoria L. Harris at 936-1164.