Half of AIDS Patients Are Now Drug Resistant

Actual number may be higher because statistics studied are a few years old

TUESDAY, Dec. 18, 2001 (HealthDayNews) -- In another dose of bad news on the AIDS front, researchers have found that more than half the long-time HIV-positive patients have developed resistance to at least one of the drugs that could help keep them alive.

The true number may be even higher because the statistics were compiled in 1998 and 1999. "Resistance is very prevalent, and we're going to have to start thinking about resistance among the newly infected," said Dr. Samuel Bozzette, a professor of medicine at the University of California at San Diego who studied 1,647 people nationwide who tested positive for HIV, the virus that causes AIDS.

But another expert cautioned that although there is cause for concern, the prospects for patients are more optimistic than the numbers might suggest.

The three main classes of AIDS drugs aim to lower the level of the virus in the blood so a patient's immune system remains strong. Otherwise, patients become vulnerable to a large number of diseases that attack when the body's defenses are down.

However, HIV can mutate to avoid being killed by drugs, especially if the virus survives because an infected person forgets to take his medicine.

Doctors usually anticipate the possibility of resistance and put patients with HIV or AIDS on a "cocktail" of medications from the three classes of drugs. If one drug doesn't work, doctors hope the others will kick in.

Bozzette and his colleagues studied the blood of patients tested in 1998 and 1999. They had all been HIV-positive during an earlier study in 1996, when the AIDS cocktail was first developed.

Of the patients who had significant levels of the AIDS virus in their blood, 78 percent showed resistance to at least one HIV drug; 51 percent of all HIV-positive patients were resistant.

The most vulnerable were those who were still taking the drugs, giving the viruses in their bodies more time to resist the medications.

The patients were most resistant to the oldest class of AIDS drugs, known as nucleoside reverse transcriptase inhibitors. AZT, perhaps the best-known AIDS drug, is a member of that class.

The findings were scheduled to be released today at a Chicago conference sponsored by the American Society for Microbiology.

The findings show that drug resistance is a nationwide problem, not just limited to urban cities where AIDS is treated most aggressively, Bozzette said. "This is everybody -- the big providers, the small providers, the cities and the countryside."

He warned that the growing problem of drug resistance will create huge challenges for doctors.

"HIV care is going to become increasingly complex, and it's going to be with us for a long time," he said. "We know that the drugs aren't magic bullets, but they're going to require aggressive and sophisticated management. Handling people who are resistant to one or two drugs is quite difficult."

Another problem looms on the horizon. As drug resistance increases, a larger number of people will be infected with HIV strains that are already immune to AIDS drugs, Bozzett said. Instead of developing that immunity over time, the newly infected will have it from the beginning.

On a brighter note, experts say the number of HIV patients with resistance to all three classes of AIDS drugs appears to be rare.

Although the idea of a drug-resistant strain of HIV sounds scary, researchers note that the mutated forms pay a price as they change their structure to avoid being killed.

"As they learn a new trick, they forget the old tricks to some extent," said Dr. Robert M. Grant, an investigator at the University of California at San Francisco, in a recent interview.

It's not clear if people who become resistant to drugs actually die earlier than those who don't, said Dr. Joshua Bamberger, medical director for housing and urban health with the San Francisco Department of Public Health.

"Resistance comes in different flavors, and some is bad and some isn't," he said. "The fact that there's resistance out there doesn't mean that people should stop taking meds. They prolong life and prevent opportunistic infections."

Bamberger added that doctors should work harder to make sure that patients follow their complicated drug regimens. In San Francisco city programs, patients receive plastic pill kits that line up their medications according to the times they are to be taken.

Unfortunately, he said, this practice is not common nationwide.

What To Do

This Gay Men's Health Crisis fact sheet has more about protease inhibitors.

Learn more about drug resistance and AIDS from AIDSmeds.com, which is supported by drug companies.

Find out the basics of AIDS treatment at The Body.

SOURCES: Interviews with Samuel A. Bozzette, M.D., Ph.D., professor of medicine, University of California at San Diego; Robert M. Grant, M.D., investigator, Gladstone Institute of Virology and Immunology, University of California at San Francisco; Joshua Bamberger, M.D., MPH, medical director for housing and urban health, San Francisco Department of Public Health; Dec. 18, 2001, American Society for Microbiology conference, Chicago
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