AP 11 July 2001

Chicago -- Two new studies suggest that the slight blips in virus levels that many AIDS patients experience while taking combination drug therapy do not necessarily mean the treatment is failing after all.

The findings could have significant implications for AIDS treatment. Doctors generally try to suppress the AIDS virus to levels undetectable by routine tests. Up to now, doctors believed that when HIV rises back to detectable levels, it means that the virus is becoming drug-resistant and that the patient has to switch medications.

The new studies suggest that slight, intermittent surges in virus levels do not always mean the virus is becoming drug resistant, and switching drugs may not be necessary.

"Unnecessary regimen switching may result in disruption of a patient's medication routine, toxic effects from new drugs, and premature discarding of useful drugs," according to one of the studies, led by Dr. Diane Havlir of the University of California in San Diego.

The studies were published in today's Journal of the American Medical Association.

The studies "question some of the basic principles upon which therapy is based," said Dr. Steven Deeks of the University of California in San Francisco's AIDS Program, who wrote an accompanying editorial. The findings indicate that "complete viral suppression is rarely achieved with current therapies." Patients in both studies received standard drug cocktails of the older AIDS workhorse medications AZT and 3TC, plus protease inhibitors, which have transformed the disease into a manageable chronic ailment for many patients.

Havlir and colleagues analyzed data on 241 patients followed for about 16 months and a group of 13 followed for about 4 1/2 years.

"Intermittent viremia" - occasional, detectable AIDS virus levels - occurred in about 40 percent of the 241 patients and in six of the 13. Persistently high virus levels indicating the treatment failed occurred in 30 patients, but were no more likely to occur in those with virus blips.

In the other JAMA report, Dr. Deborah Persaud from Johns Hopkins University Children's Center and colleagues studied blood samples of 20 AIDS patients on standard drug treatment for at least two years. They found that standard treatment seemed to block virus mutation even in patients with intermittent blips of virus activity. The AIDS virus develops drug resistance by mutating.