AIDS Pill Shows Promising Results in Study

A biotech firm in Foster City, Calif., said Tuesday that its experimental, one-a-day pill significantly lowered HIV levels in the bloodstream of AIDS patients who were becoming resistant to current medicines. Mark Perry, executive vice president of Gilead Sciences, said that based on this Phase III, or final stage, clinical trial, his company will soon ask the U.S. Food & Drug Administration for approval to sell tenofovir DF. It hopes to get a positive answer by the end of this year.

As is commonly done with AIDS medications that have reached the final stage of human trials, Gilead is offering tenofovir free to the sickest AIDS patients - people with high viral loads who have become resistant to current medications. Gilead is also studying tenofovir as a first-line treatment against AIDS.

Gilead reported its findings on tenofovir after it had looked at the midway results of a 48-week clinical trial that randomly divided 552 AIDS patients into two groups.

Half of the patients received tenofovir in addition to the standard cocktail of AIDS drugs. The other group received their AIDS cocktail and a placebo. Neither the doctors nor the patients in the experiment knew whether they were in the drug or placebo group.

To qualify as a volunteer, all 552 patients had to have high levels of HIV in their bloodstream and had to have been taking AIDS medications for at least five years. As a part of the experiment, scientists tested the volunteers for drug resistance. They found that more than half the patients were becoming resistant to one or more of the current AIDS drugs.

After 24 weeks of the trial, Gilead compared the two sets of patients. It reported yesterday that patients in the tenofovir group had experienced an average 75 percent reduction in HIV levels, according to Perry.

In the placebo group, HIV levels remained essentially flat. The higher the level of virus, the more likely a patient would experience the symptoms of AIDS, Perry said.

Kathleen Squires, an associate professor of medicine at the University of Southern California and one of the clinical leaders of the Gilead experiment, said in a statement that she was encouraged that tenofovir showed such a strong effect on reducing HIV levels.

``These are the toughest patients to treat,'' Squires said. ``After years of anti-HIV therapy, most patients have greater difficulty adhering to and tolerating multidrug regimens.''

Squires said tenofovir should be easier to take than current AIDS cocktails because it ``has the added benefit of being administered as a simple, one-pill, once-daily dose.''

Gilead continues to gather data on the side effects of prolonged exposure to tenofovir, which is an improved version of an experimental drug called adefovir. In 1999, an FDA advisory panel rejected Gilead's bid to sell adefovir because the drug seemed to cause too much kidney damage.