RENEE MONTAGNE, host:
A panel of advisers to the Food and Drug Administration meets today to review a new kind of anti-AIDS drug. If the panel recommends its approval, the new drug would expand options for people infected with HIV who have become resistant to current medications.
NPR's Brenda Wilson reports.
BRENDA WILSON: There are up to 30 anti-AIDS drugs now available to treat people with HIV. They all slow the virus down by attacking two main enzymes.
Dr. Mark(ph) Markowitz is the clinical director at the Aaron Diamond Research Institute. He says that the new drug, raltegravir, is the first to attack another enzyme called the integrase.
Dr. MARTIN MARKOWITZ, (Clinical Director, Aaron Diamond AIDS Research Center): Integrase is one of the enzymes that the virus codes for that is required for the virus to make new copies of itself. And to date, there are no drugs that are currently approved to treat HIV infection that target this particular enzyme.
WILSON: That means that raltegravir is the first in its class of what is called an integrase inhibitor.
Dr. MARKOWITZ: What the integrase inhibitor does is binds to the enzyme and prevents the enzyme from taking the virus' genetic material and allowing it to integrate into the DNA of the host. And that's required for HIV to complete its life cycle. So if you prevent that, then the virus can't make new copies of itself.
WILSON: The drug would be used in combination with current anti-retrovirals. The drug manufacturer Merck is hoping that the advisory panel of the FDA agrees that its version of raltegravir is both safe and effective and serves an important niche.
Dr. MARKOWITZ: There are people who have been taking drugs for a long period of time who have virus that's resistant to some of the drugs that are currently available to treat HIV infection. So by having a new target, you can basically predict that essentially all viruses are going to be susceptible to this drug.
WILSON: In all likelihood, until more it's known about raltegravir, that is how it will be used - for people who have exhausted other combinations of therapy. So far, in small studies, it appears to be as safe and effective as other drugs that are used to treat patients who have just been diagnosed. And there are indications that raltegravir may have other potential as well. When compared with some anti-AIDS drugs, it appeared to be even more effective in suppressing the virus.
Dr. Ken Mayer is a professor of medicine and community health involved in AIDS research at Brown University.
Dr. KEN MAYER (Professor, Brown University): Just like in the old days, when we didn't know whether adding a third drug would make a big difference - and we found out it really did - only time will tell how much of a breakthrough this may be.
WILSON: Perhaps, he says, if the virus is attacked at the earliest stage of infection, using combinations of drugs that attack a variety of targets, the progression of the virus could be dramatically altered, eradicated even. And there are studies looking into different approaches to HIV therapy using the new drugs.
Mayer spends a lot of time working in developing countries. This new drug serves once again as a reminder to him of the discrepancies in HIV care between rich and poor countries when older, so-called first-line treatments begin to fail.
Dr. MAYER: There are now several million people now on anti-retroviral therapy but they're on first-line for the most part. So I think this does heighten the need to think about how to get cheaper second-line and third-line drugs available.
WILSON: Raltegravir is just another in a series of new, costly anti-AIDS drugs, and there are others on the way that provide new mechanisms for attacking an old virus, a virus of many parts.
Brenda Wilson, NPR News. Transcript provided by NPR, Copyright NPR.
