HIV treatment interruptions, or so-called drug holidays, may be dangerous in patients whose virus has become drug-resistant, a new study released Wednesday showed. Treatment breaks helped the disease progress faster and did little to save lives or improve the quality of health when signs of drug resistance were appearing, researchers reported in Thursday's edition of the New England Journal of Medicine. "We had hoped that a structured treatment interruption would be beneficial for people experiencing treatment failure due to multidrug-resistant HIV," said Jody Lawrence of the University of California, San Francisco, who led the study. "However, our results indicate that this strategy does not work and should be avoided by this group of HIV-infected individuals. Continuing therapy guided by HIV drug-resistance testing proved to be a better approach."
Drug holidays are being tried in a variety of HIV patients to get a break from the side effects of the drugs. Doctors considered interrupting treatment once resistance to the drugs has developed because, when the drugs are stopped, the AIDS virus tends to mutate back to a form that is more sensitive to the highly active antiretroviral therapy. The researchers did find that in 64% of the 138 test patients whose treatment was interrupted for 16 weeks, the virus indeed reverted to a more sensitive form. However, those people did not do as well when resuming anti-HIV drugs as did the 132 patients who were immediately switched to new medicines without a treatment break. HIV disease progression, as marked by falling T-cell counts and rising HIV viral loads, was detected in 16% of the patients who took a drug holiday and then resumed medication, compared with 9% of those who switched to a different HAART cocktail.
Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, which sponsored the research, cautioned that the new study included only cases where HIV was detectable in the blood and the virus had become resistant to anti-HIV drugs. "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," Fauci said in a statement.