Study: Cycling Drugs May Curb AIDS

Tuesday, December 4th 2001, 12:00 am
By: News On 6

WASHINGTON (AP) _ It may be possible for AIDS patients on a powerful drug combination to take weeklong medication vacations and still control HIV, while cutting costs by half and reducing serious side effects, a study suggests.

Federal researchers, whose findings appeared Tuesday in the Proceedings of the National Academy of Sciences, said a small group of patients in their study was able to successfully follow a drug regimen of one week on and one week off the antiretroviral medications.

``If further studies bear out what we've seen so far, it will mean that you can reduce the cost of therapy by 50 percent,'' said Dr. Mark Dybul, a clinical researcher at the National Institute of Allergy and Infectious Diseases, which is one of the National Institutes of Health.

He said the study also suggests the on-again, off-again approach may lower the toxicity of the drugs enough to give ``a dramatic improvement in a patient's quality of life.''

This effect is less certain than is the reduction in costs, said Dybul, ``but it is very promising.''

International AIDS experts said if the intermittent drug therapy approach proves successful in studies with more patients, it could have a dramatic effect on the HIV epidemic in third world countries, where the expense of the drugs often prevents patients from being treated.

Jose M. Zuniga, president of the International Association of Physicians in AIDS Care, said that results of the NIAID study ``are extremely encouraging'' and should be expanded into studies involving many more patients.

``They merit increased studies because of the potential revolution of this type of medical management'' in countries with limited resources, said Zuniga, whose organization represents 10,800 doctors and health care workers in 83 countries.

``This is a very welcome development,'' said Hans P. Binswanger of the World Bank. He said international agreements have helped reduce the cost of HIV drugs in some African countries to about $500 per patient, per year, but even this is too much for many patients.

By cutting the cost in half, Binswanger said, many more patients would be able to receive the drugs.

Dr. Jeffrey Laurence of the American Foundation for AIDS Research said the study is ``good news'' for the AIDS community, but cautioned that the cycling therapy has only been used experimentally in a small group of select patients. He said it should not be followed by the 1 million Americans infected with HIV except under the direction of a doctor in a controlled trial.

``I don't recommend that patients try this at home,'' said Laurence.

Dybul agreed, noting that it will take a much larger clinical trial to prove that the intermittent therapy is appropriate and safe for all HIV patients.

In the study, Dybul and his NIAID colleagues selected 10 HIV patients whose disease was being controlled by highly active antiretroviral therapy, or HAART. This involves a rigid daily schedule of taking a cocktail of drugs which inhibit the reproduction in their bodies of the HIV virus.

The drugs were working well in all the selected patients _ the level of virus in their blood was depressed, while the number of CD4 cells in their blood was at a good level. CD4 cells, which are crucial to a healthy immune system, are the main targets of the HIV virus and can quickly become depleted by the infection.

Dybul said the 10 patients were put into a program where they took the drugs as before for seven days and then stopped for seven days. The experiment continued for up to 88 weeks. Blood tests showed the virus infection continued to be suppressed in all the patients who maintained the schedule, he said. Two patients were dropped from the study because they failed to take their drugs as required, said Dybul.

As for side effects, Dybul said cholesterol levels in the patients dropped by an average of 22 percent, while triglyceride levels were halved. High cholesterol and triglyceride levels, along with a shift of fat deposits in the body, is a major side effect of the HIV therapy. Some patients develop thick fat pads in the back and around the abdomen. Other side effects include diabetes, hepatitis and lethal levels in the blood of lactate acid.

Learning how to combat these side effects and lower the drug cost are important, said Dybul, because it is clear that the current group of antiviral drugs can control HIV infection, but not cure the virus. Once the drugs are halted for more than a week, the infection can come roaring back, he said.

``This means that these patients will be on the drugs for the rest of their lives,'' said Dybul.

As a result, he said, researchers are trying to find ways to maintain the good effects of the drugs, while eliminating the toxic effects and lowering the costs.