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NC Now: HIV/AIDS Research
More than 40 million people worldwide live with HIV and AIDS, according to the United Nations. Before the decade is over, researchers estimate anywhere from 25 to 40 million children in Africa will lose their parents to AIDS. Experts say the message is clear: AIDS is a worldwide health emergency. World-renowned researchers in North Carolina's Research Triangle are playing a big part in working to stop it.
At Duke University Medical Center, scientists work feverishly to develop a vaccine for AIDS, something that will make it just as preventable as the measles, mumps, or polio. But they say AIDS presents a special set of challenges.
Dr. Bart Haynes/Director, Human Vaccine Institute: This is a rapidly mutating virus and the virus that you have today in a community is not the same virus one will have five years from now, so the AIDS virus is a moving target.
Dr. Bart Haynes heads Duke University's Human Vaccine Institute and has worked on AIDS since the early days of the epidemic. He says that notion of a "moving target" has forced researchers to look for new strategies to fight the disease. One involves analyzing more than 100,000 different sequences of HIV to come up with a vaccine that will prevent as many of them as possible.
Dr. Haynes: We've gotten supercomputers to work on these sequences to come up with what's called consensus sequences, which are artificial sequences that are more like all the other sequences in the database than any other individual wildtype sequence might be. And so we're studying these for their ability to induce more broad immune responses than might be available through other wildtype viruses that we might isolate from a patient in a given location.
Dr. Haynes says animal testing of these artificially created compounds looks promising, but the institute is not putting all its eggs in that basket. He says another team of scientists is taking a totally different approach.
Dr. Haynes: That is taking many different specific wildtype genes – that is, genes isolated from individual patients – and mixing them together, the so-called polyvalent approach, and so because the epidemic is moving so fast we're doing everything all at once. So instead of doing one after the other we're doing them all in parallel.
But he says it is possible there might never be a vaccine that totally prevents HIV infection, not only because the virus mutates so quickly but also because it's difficult to get the right kind of immune system response.
Dr. Haynes: So I think the first thing we'll see is a vaccine that prevents disease or retards disease or causes a less severe disease, and how effective that vaccine's going to be, as I say, is a real critical question which is going to be answered soon. In reality, while we all hope there's going to be a major breakthrough and we're going to find a vaccine candidate that works in all people against all strains, I suspect that what has already started to happen will continue to be what we'll likely see and that is we'll take our best candidate today and put that in clinical trials and it will induce a certain level of immune response and a certain breadth of immune responses for a certain number of strains. Then we'll take that and make it better and go to the next clinical trial.
Those clinical trials study both the safety and the effectiveness of potential vaccines. Duke's Dr. Kent Weinhold plays a major role in that aspect of research. It was in his lab years ago where researchers first proved the effectiveness of AZT, the first aids drug, which is now a cornerstone of AIDS treatment. Today Dr. Weinhold oversees the central laboratory for the International HIV Vaccine Trials Network.
Dr. Kent Weinhold: So we direct the efforts that are aimed at measuring immune responses in these candidate AIDS vaccines. Are they recognizing components of the vaccine, are they recognizing it in a way that we think would be beneficial ultimately to prevention of infection or control of infection?
He says it's tedious and sophisticated work. Potential vaccines must pass two stages of human testing before they reach large-scale, phase three clinical trials, a process that takes a great deal of time.
Dr. Weinhold: It usually takes five years of evaluation before you know efficacy. There is a chance that if you have something highly efficacious you're going to see a difference between placebo and vaccine recipients very quickly that may be within two or three years, so on that time scale we're talking very optimistically five to six to seven years. On a more pessimistic timeline, if we have to go back to the drawing board and develop whole new strategies then we're talking 10 to 20 years.
Researchers worldwide agree they don't have that kind of time, so work is also focusing on other prevention strategies. One is microbicides.
Dr Laneta Dorflinger/Family Health International: Microbicides are products that women can use vaginally to help prevent, or more appropriately, to reduce their risk of acquiring a sexually transmitted infection. They can be gels, or they can be little films which are almost like a piece of paper cut into a square, or tablets or capsules.
Dr. Laneta Dorflinger is the Vice President for Clinical Research at Family Health International, which has studied contraceptives and sexually transmitted infections for several decades. The lab we visited tests condoms, and part of the work involves making sure microbicides will not damage the latex. Dr. Dorflinger says there are several types of microbicides in development.
Dr. Dorflinger: Some provide just a barrier. Some actually can kill the different STIs and HIV, and others which are targeted specifically against HIV can actually prevent its replication when it gets into cells.
Dr. Dorflinger says a microbicide could be on the market within five to seven years and have a great impact on the spread of HIV.
Dr. Dorflinger: Women all over the world will be able to access these products and make decisions for themselves. It's nice when you can negotiate things with your partner, but that's just not always possible, and I think it's very, very important that women have these options that they can use themselves.
Another aspect of research is treatment. UNC-Chapel Hill's Center for AIDS Research is a national leader. UNC's AIDS Clinical Trials Unit has dozens of studies underway looking at everything from drug therapies to fighting complications of AIDS.
Drug makers like GlaxoSmithKline are also working on new treatments. Its research and development on AIDS drugs is headquartered in RTP, and scientists there say their top goals are finding drugs that will combat resistant strains of HIV and making treatment regimens easier for patients. But what about a cure? Scientists say it would be great, but it's not likely because even with the best therapies, HIV can stay dormant in the body for years.
Dr. Weinhold: Until we develop a strategy to get at those latent reservoirs, I don't think we can really talk about a cure, so I think more realistically we're talking about trying to put HIV in with diabetes and other chronic diseases, manage it as a chronic disease. That's a more realistic goal.
There are many other researchers at public and private institutions throughout the Research Triangle area that are also working on AIDS vaccines and treatments. Family Health International says there is more federally-funded AIDS research there than in any other metropolitan area in the country. |
