Doctors Report HIV Drug Breakthrough

MELVILLE, N.Y. _ A drug that zeros in on a novel HIV target and disables a key link in the infection process can successfully treat patients who have failed other therapies, Stony Brook University doctors have found.

Dr. Roy Steigbigel, chief of Stony Brook University Medical Center’s HIV program, said there is a new class of anti-viral medications called integrase inhibitors that can “rescue people on a downward curve,” those for whom resistance has made treatment difficult.

The medication Steigbigel and his team studied is raltegravir (sold as Isentress), the first drug in this new class. The drug attacks a viral enzyme called integrase, which facilitates the integration of HIV’s genetic material into a person’s chromosomes, and disables it. Integrase has never before been tackled in HIV therapy.

“The study was done in people who had demonstrated resistance to at least one drug,” said Steigbigel, who reported results of the international study involving nearly 700 people in this week’s New England Journal of Medicine.

In the research, patients received raltegravir, manufactured by Merck & Co., in combination with other routinely prescribed HIV medications, or they received a placebo in combination with traditional drugs.

At the end of the 48-week project, Steigbigel found that 62 percent of patients who took raltegravir experienced a dramatic drop in HIV from about 400 viral copies per milliliter of blood to below 50 viral copies per milliliter. Only 35 percent of a control group that did not receive the drug but still took the traditional drugs had a similar decrease.

Despite the fact that drug treatment over the past 12 years has transformed HIV from the inevitability of full-blown AIDS into a condition manageable as a chronic illness, a problem for many has been that of drug resistance _ the virus repels medications designed to destroy it.

“Our practice here at Stony Brook is probably representative of most,” Steigbigel said. “About one-third of the patients have a problem with marked resistance. And as time goes on, most patients will have a problem with it.”

Currently, doctors have a choice of about 25 medications, which are prescribed in combinations of about three, the so-called drug cocktails. The cocktails were designed to extend life and ward off resistance. But resistance, albeit nowhere near what it was two decades ago, persists despite the strategy.

Even though Steigbigel praises the use of cocktails, he said patients need new drugs that work in novel ways.

Steigbigel noted that medical science still has a long way to go to overcome the worldwide problem of resistance, which is caused by a variety of factors. Many people who are newly infected, he said, are acquiring resistant HIV strains from those already under treatment. Additionally, viruses become immune to the medications when patients do not faithfully take them.

“Many of these medications have some really horrific side effects,” said Catherine Hart, executive director of the Long Island Association for AIDS Care. Steigbigel said the most common side effect of raltegravir was elevated cholesterol.

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