Study: Cycling Drugs May Curb AIDS

A study by federal researchers at the National Institute of Allergy and Infectious Diseases (NIAID), published online today in the Proceedings of the National Academy of Sciences -- "Short-cycle Structured Intermittent Treatment of Chronic HIV Infection with Highly Active Antiretroviral Therapy: Effects on Virologic, Immunologic, and Toxicity Parameters," Mark Dybul, et. al., (December 04, 2001) -- offers encouraging news for AIDS patients on antiretroviral medication. (The early edition can be found at: http://www.pnas.org/cgi/content/abstract/261568398v1.)

The researchers found that a small group of patients was able to successfully follow a drug regimen of one week on and one week off antiretroviral medications. This may mean that AIDS patients on the powerful combination drug regimen can take weeklong vacations from the regimen and still control HIV.

In the study, Mark Dybul, a clinical researcher and his NIAID colleagues, selected 10 HIV patients on highly active antiretroviral therapy (HAART). All participants had low levels of the virus with high levels of CD4. Patients took HAART in the standard way that they had taken the regimen before for seven days and then stopped for seven days for up to 88 weeks.

Serological tests indicated that the virus levels were maintained at the suppressed level in all patients who stayed with the schedule. Two patients were dropped from the study failing to take the drugs as required.

Some side effects were reduced in the experimental group. According to Dybul, cholesterol levels dropped by an average of 22 percent, and triglyceride levels were decreased by 50 percent. Dybul said that 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. "This means that these patients will be on the drugs for the rest of their lives," said Dybul.

Dybul stressed that a much larger clinical study is needed to indicate that the intermittent regimen is appropriate and safe for all HIV patients. And Dr. Jeffrey Laurence of the American Foundation for AIDS Research said the study is "good news" for the AIDS community, but he cautioned that the cycling therapy has only been used in a small group of 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.

"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 Dybul. The additional gains of lowering the toxicity of the drugs he suggested could bring about "a dramatic improvement in a patient's quality of life." This conclusion is not as certain as the cost reduction, said Dybul, "but it is very promising."

The study has drawn voices of optimism from various quarters. International AIDS experts said if the intermittent drug therapy approach proves successful in other studies, it could have a dramatic effect on the HIV epidemic in developing countries, where the expense of the regimen often prevents patients from being treated. Jose M. Zuniga, president of the International Association of Physicians in AIDS Care, said that the results of the NIAID study "are extremely encouraging" and should be expanded into larger studies. "They merit increased studies because of the potential revolution of this type of medical management" in countries with limited resources.

"This is a very welcome development," said Hans P. Binswanger of the World Bank. By cutting the cost in half, Binswanger said, many more patients would be able to receive the drug.

Back to other CDC news for December 4, 2001

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