Miami Herlad - Wednesday, December 19, 2001

An estimated four of five people in the United States with detectable virus have developed resistance to at least one drug in the AIDS medicine cabinet, a discovery revealed at a national gathering of infectious-disease experts in Chicago. And 51 percent of those patients have exhausted drugs in at least two of the three classes of AIDS medicines.

The implications are dire: A virus that once seemed on the verge of containment could begin rampaging like wildfire, beyond the reach of drugs promising to transform AIDS into a chronic but treatable condition.

"It's very sobering," said Dr. Nicholas Hellmann, an author of the study. "HIV is a very savvy virus, and it can mutate as rapidly as we can identify new drugs. It's going to continue to evolve, and there's no drug currently available or on the horizon that is immune to this rapid resistance development."

The peril of drug resistance extends beyond people already infected -- studies have shown that resistant virus can be transmitted from person to person, by sexual contact and intravenous drug use.

S. FLORIDA EFFECT

With Miami-Dade having the third highest rate of infections in the country, the implications of the new findings are particularly serious for South Florida.

"We know that drug resistance has been an increasing problem -- it has been getting worse and worse," said Dr. Michael Wohlfeiler, a South Beach internist who specializes in treating AIDS. "I don't think many people thought it had gotten this bad.

"It's scary stuff."

But just how scary remains a point of scientific conjecture.

Dr. Margaret Fischl, the University of Miami AIDS expert regarded as a top researcher in the disease, challenged the current relevance of the study released at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.

The team of scientists who did the research analyzed blood samples drawn in 1999 from 1,647 men and women participating in a national HIV study.

In order to do their scientific work, the researchers had to use blood with detectable levels of the virus. That meant patients whose virus had been quashed to unmeasurable levels were not included.

Even assuming that all of those patients had no drug-resistant strains -- an improbable scenario -- the researchers figured at least 50 percent of all people with a history of HIV have resistance to at least one drug.

"One needs to be cautious in the interpretation of the study," Fischl said Tuesday from her office in Miami.

That's because the sample of patients studied represents the first generation exposed to triple-drug therapies, anchored by a cadre of medicines known as protease inhibitors, which became widely available in 1996. In those first years after the arrival of the protease drugs, physicians and patients experimented with combinations, taking one drug and letting time pass, then a second, then a third.

"You really need three drugs together -- at the same time -- because that provides the greatest genetic barrier and the greatest push to keep the virus suppressed," Fischl said.

DRUG REGIMENS

Today, when patients decide to begin taking drugs, they often start with the multiple-drug regimens. And medicines more recently developed possess greater strength, some with 30 to 40 times as much HIV-battling muscle.

Thus, Fischl concludes that levels of drug resistance are probably lower than what researchers found in their review of 1999 blood samples.

Hellmann, the study author, does not share Fischl's assessment. The research, paid for with public and private money and centered at the RAND research agency in California, was led by an infectious-disease specialist who directs AIDS research centers at the San Diego Veterans Affairs Medical Center and the University of California-San Diego.

"Hopefully, as we introduce more and more therapy, you get slower rates of resistance development -- that's a hope," said Hellmann, vice president of clinical research for ViroLogic, a South San Francisco biotech company that has developed tests to detect drug-resistant AIDS virus. "But we don't have the data to give you a current estimate."

Those tests, which are becoming widely available, help physicians decide on the most effective treatments for patients. It is part of the quest to remain one scientific step ahead of a cunning virus.

"The trick," said Richard Levy, vice president for scientific affairs at the National Pharmaceutical Council, a research and education initiative started by the drug industry, "is to outrun it by coming up with new drugs all the time."

The reasons for the emergence of drug-resistant strains have much to do with the molecular ingenuity of the virus -- and the complexity of the drug regimens that have tamed the disease in patients once desperately close to death. Those treatments prove so arduous that some patients skip doses, a practice known as drug holidays. And that gives the virus time to figure out ways to thwart medicines.

That is why some people with the virus wait longer to begin taking pharmaceutical cocktails that consist of a fistful of pills every day.

Sheri Kaplan is one of those people.

"I want to preserve my options, preserve my army of assistance for when my body needs it the most," said Kaplan, executive director of Positive Connections, a North Miami AIDS service agency.

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Always watch for outdated information. This article first appeared in 2001. This material is designed to support, not replace, the relationship that exists between you and your doctor.

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