Drug Resistance Gaining Again
In AIDS Treatment
By Ben Hirschler
European Pharmaceuticals Correspondent

BARCELONA, Spain (Reuters) - Drug resistance has returned as a mounting problem in HIV/AIDS treatment, after a brief lull in the late 1990s, according to new figures released Saturday.
The introduction of triple-drug therapies in the mid-1990s revolutionized the treatment of the killer disease for thousands of those infected in Western countries, allowing them to return to relatively normal lives.
But the virus is fighting back by evolving new ways to circumvent medicines. A growing number of people are being infected with strains that are already resistant to one or more of the three widely used classes of antiretroviral drugs.
Dr. Frederick Hecht of San Francisco General Hospital, speaking to reporters before the opening of the week-long conference in Barcelona on acquired immune deficiency syndrome (AIDS), saw a rising danger of complacency.
If people believe the human immuno-deficiency virus (HIV) that causes AIDS can be easily kept at bay by popping a few pills, they could be putting themselves at risk, he said.
"There has been a decrease in caution about avoiding HIV infection and an increase in riskier sexual behavior...on the assumption that HIV is much (more) readily treated now," he said.
"That idea needs to be called into question because some people are becoming infected with (a strain of) virus that is going to be much more difficult to treat," Hecht said.
In a five-year study of 225 patients with recently acquired HIV infections, Hecht and his colleagues found 16 percent of new cases were now caused by a strain of virus resistant to at least one drug class.
Resistance to non-nucleoside reverse transcriptase inhibitors -- a widely used and potent type of AIDS medicine -- had increased from zero to 13.2 percent from 1996-97 to 2000-01.
At the same time, genetic fingerprinting of the virus found in patients' blood showed that resistance to protease inhibitors had grown from 2.5 to 7.7 percent.
Meanwhile, resistance to the original class of anti-AIDS drugs, known as nucleoside reverse transcriptase inhibitors and including AZT, had shown an alarming increase to 21 percent, after dipping to seven percent in 1998-99.
The results were published in a special edition of the Journal of the American Medical Association.
Hecht said San Francisco was in the vanguard of HIV/AIDS treatment, so the worrying trend of rising drug resistance was likely to be replicated elsewhere.
"I think we are going to see continued increases (in resistance) over the next two years," he said.
The problem could have particular implications in developing countries, many of which are expected to rely heavily on combinations of relatively cheap reverse transcriptase inhibitor drugs rather than more expensive protease inhibitors.
In the United States, the issue of drug resistance was forcing doctors to test ever more complex regimes.
Dr. Scott Hammer of Columbia University College of Physicians and Surgeons in New York City reported on another clinical trial showing for the first time that adding two protease inhibitors, rather than just one, to drug cocktails could help patients who had failed to respond to other treatments.


This Site Served by TheHostPros