U.S. halts HIV
treatment interruption study

The U.S. government has halted enrollment in a major international study of drug-conserving anti-HIV drug therapy, after patients trying the on-again, off-again medication strategy got sicker than those who never took a break from their anti-HIV drugs.

The study had enrolled more than 5,000 HIV patients in 33 countries, including the United States, when a routine safety analysis detected that patients being given medications only when their immune systems waned were more than twice as likely to have the disease progress as people who took those high-powered drugs continuously.

That was a surprise: Earlier, albeit smaller, studies had suggested that it might be possible to take medication breaks and still control HIV--while reducing serious side effects and cutting costs. If this on-again, off-again approach had panned out, it would have been a particular boon in developing countries, where many patients cannot afford antiretroviral therapy.

But the National Institutes of Health ordered a much larger study to be sure those early results were real. Called the SMART trial, for Strategies for Management of Antiretroviral Therapy, volunteers were randomly assigned to take their medicine all the time or only when key immune cells called CD4 cells dropped to a certain level.

Not only did that strategy not control HIV--there actually was an increase in side effects affecting the heart, kidney, and liver in patients taking the drugs only episodically.

Study sites also included Argentina, Australia, Austria, Belgium, Brazil, Canada, Chile, Denmark, Estonia, Finland, France, Germany, Greece, Ireland, Israel, Italy, Japan, Lithuania, Luxembourg, Morocco, New Zealand, Norway, Peru, Poland, Portugal, Russia, South Africa, Spain, Switzerland, Thailand, the United Kingdom, and Uruguay. (AP)