Drug holidays show no benefit in drug-resistant HIV

November 1, 2003

Pharmaceutical Representative

Pharmaceutical Representative-11-01-2003,

Prescribed interruptions in antiretroviral therapy may hasten disease progression in HIV patients whose treatment has been rendered significantly less effective by the development of resistance to multiple anti-HIV drugs.

Prescribed interruptions in antiretroviral therapy, known as drug holidays, may hasten disease progression in HIV patients whose treatment has been rendered significantly less effective by the development of resistance to multiple anti-HIV drugs, according to a study in The New England Journal of Medicine (vol. 349, no. 9).

Researchers supported by the National Institute of Allergy and Infectious Diseases found that study participants who underwent a four-month structured treatment interruption had more HIV-related complications and poorer immune response than did individuals who took antiretroviral drugs continuously throughout the study.

As used in this study, structured treatment interruption involves discontinuing all anti-HIV drugs for a defined period of time to allow the repopulating virus to regain susceptibility to anti-HIV drugs. Previous studies of individuals infected with multiple drug-resistant HIV have shown that drug-sensitive variants of the virus re-emerge and become predominant after therapy is stopped. Treatment interruptions have also been used to give people time off from multiple medications that may be difficult to take and have toxic side effects.

"We had hoped that a structured treatment interruption would be beneficial for people experiencing treatment failure due to multidrug-resistant HIV," said study chair Jody Lawrence of the department of medicine at the University of California, San Francisco. "However, our results indicate that this strategy does not work and should be avoided by this group of HIV-infected individuals."

Details of the study

The study enrolled 270 participants with multidrug-resistant HIV who had HIV levels of more than 5,000 copies per milliliter of plasma. About half of the participants were randomized to a four-month interruption of treatment before starting a new, optimized anti-HIV treatment regimen. The remaining patients were placed in a control group and immediately started a new, optimized regimen.

After an average follow-up of nearly 12 months, 22 of the 138 individuals in the treatment-interruption group had either died or experienced disease progression, compared with 12 of the 132 people in the control group. Participants in the treatment-interruption group also had persistently fewer CD4 T-cells and showed no benefit in HIV viral load response or quality of life relative to the control group.

"It is important to remember that the failure of treatment interruption seen in this study pertains only to individuals who had drug-resistant HIV and detect-able virus in their blood when they entered the study," said NIAID Director Anthony S. Fauci. "For individuals who are being successfully treated with anti-HIV medications, other studies have shown that cycles of treatment interruptions for shorter periods may be of potential benefit to conserve medications and reduce drug-related toxicities." PR

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