CNN HEALTH Special Section

Researchers want to know if anti-HIV drugs eliminate the virus

In this story:

• Other tests have lowered dosage
• If virus rebounds, volunteers go back on drugs
• Related links and stories

From Medical Correspondent Elizabeth Cohen

(CNN) -- New anti-HIV drugs have greatly reduced the death rate from AIDS during the past two years. But now, researchers want to take some patients off the drugs to test whether they actually eradicate the virus.

In many patients, the newest generation of HIV drugs, called protease inhibitors, have brought HIV down to levels so low that the virus is undetectable in blood tests. The question remains, however, whether the drugs eradicate the virus or merely keep it in check.

Researchers at the National Institutes of Health plan to ask 50 patients to go off the drugs completely. Doctors in Boston are doing a similar experiment.

"It's sort of hard (for patients to imagine), 'If I'm doing OK and the virus is under control, why would I ever want to be in an experiment?'" says medical ethicist Arthur Caplan. "But these are not medicines that are just neutral. You get nasty side effects from these things."

Common side effects from protease inhibitors include vomiting, diarrhea, blurred vision and dangerously high cholesterol levels. The regimen is demanding and expensive -- requiring up to 40 pills a day at a cost of $12,000 to $20,000 a year.

The experiments may determine if patients can be weaned from drugs

The experiments now under way may help answer the question of whether people with HIV might at some point be weaned off the drugs.

Some doctors are taking a slightly different approach. Instead of taking patients off the drugs, they have instead lowered the dosage.

For instance, in a study published in the latest issue of the New England Journal of Medicine, subjects were told to take only one or two drugs, rather than the three-drug combination usually prescribed. But as many as 25 percent of the patients say their HIV levels increase.

NIH doctors say those results, while disappointing, don't worry them because their volunteers must have had undetectable HIV levels for at least a year, compared to three to six months in the study published in the New England journal.

"You very likely have to treat people for a considerably longer period of time if you're going to even think of loosening up or letting down the intensity of the regimen," said Dr. Anthony Fauci of the NIH.

Fauci cautioned that patients who are not part of the experiment should not stop taking the drugs on their own. The volunteers will be monitored for any rebound of the virus and will be put back on the drug regimen if necessary.