JEFFREY BROWN: And finally tonight: What’s behind the excitement surrounding a potential new way of preventing AIDS?
Margaret Warner has that story.
MARGARET WARNER:In the world of science and medicine, it’s not often that researchers’ findings win a standing ovation, but that’s what happened today at the International AIDS Conference in Vienna over news of a potential breakthrough in preventing HIV among women and girls.
A two-year study of nearly 900 women in South Africa found a new vaginal gel containing the antiretroviral drug tenofovir significantly reduced the rate of new HIV infection. Among women who used the gel before and after sex three-quarters of the time, infection was cut 39 percent.
Among those who used it even more frequently, infection dropped 54 percent. This is the first time a vaginal product or microbicide has shown real promise for preventing AIDS. That’s important for women, especially in Africa, where they account for 60 point of HIV infections.
For more about the study and its significance, we’re joined from Vienna by Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases.
And, Dr. Fauci, welcome.
How big is a development is this?
DR. ANTHONY FAUCI, director, National Institute of Allergy and Infectious Diseases: Well, it really is quite significant, in that it’s a very important proof of concept of something that we have really failed at over the last several years. And that is to develop what we call a topical microbicide, which is a substance that a woman can by herself insert into her vagina that contains an antiretroviral drug or an anti-HIV drug that would block infection.
And it’s very important, because it’s been shown for the first time in several years of research on microbicides that it does in fact protect a significant proportion of the women who use it. It was a — what we call a placebo control trial, where half the women got a gel with no medication in it, and the other half got the gel with this anti-HIV medication in it.
So, the answer to your question is, really, it is a significant advance towards getting a very important type of protection that women can use themselves, without their male partner knowing about it. So, in essence, it empowers women, which is very important, particularly in the developing world.
MARGARET WARNER:And it’s relatively cheap, isn’t it?
DR. ANTHONY FAUCI: Yes, it is. I mean, I can’t give you a price on it, but a gel, the gel itself is a very common formulation.
And they’re using 1 percent of solution of a drug in there. So, I can’t imagine that this is going to be an expensive proposition at all.
MARGARET WARNER:Well, as you said, a half-dozen microbicides have been tested over the last 15 years, but with no success. Why do you think this one works?
DR. ANTHONY FAUCI: Well, the others were — were not utilizing the principle of actually putting a specific anti-HIV drug in the gel.
The gels that were used were, for example, a typical spermaticide that is used for birth control to try and disrupt the virus, which really wasn’t a very good strategy, because not only did it not work. In some of the trials, because it irritated the vaginal mucosa, it actually made women more susceptible to getting infected upon exposure.
So, it’s been a series of either no good results or results that were actually unfavorable. This is the first trial, because it used a drug that, in its oral form, is regularly used as part of treatment for HIV people who are infected. A 1 percent solution of that drug was put in the gel. And that seemed to do the trick. And that made the results really quite significant.
MARGARET WARNER:Yet, even the better result only cut the infection rate in half. Why is that?
DR. ANTHONY FAUCI: That’s the reason why I said it’s a conceptual advance, and not a ready-for-prime-time product, because there was an interesting correlation in the study.
In order for a drug or a microbicide like this to work, women have to use it religiously when they have sexual intercourse. And there was a good correlation between the women who actually adhered to the protocol and used it every time they had a sexual encounter. They had a much higher rate of efficacy.
People who used it moderately had a lower, and people who didn’t use it well at all had a much lower. So, the results that you’re talking about is the accumulation of people who used it religiously and people who didn’t do very much. So, adherence is going to have a major role.
There’s a lot of things that we need to work on. One is, first of all, confirming the trial to make sure it does work. I believe it does. I saw the data. The data looked strong.
But the other thing is, is there a better way to improve upon it? For example, there’s an ongoing trial now that uses the same product, but women use it every day, as opposed to just when they’re anticipating a sexual encounter. There are a number of other processes that are in the pipeline now, for example, a long-acting one, where you don’t have to put it in with every encounter. You may be able to maybe just put it in once, and it will be good for weeks or even longer.
I think, when we get to that point, you’re going to see better results than just the 50 percent, which, in and of itself, is better than anything we have ever seen, but the goal, the endgame, is to do better than that 50 percent.
MARGARET WARNER:If the drug were not any better than 50 percent effective, would there be a danger of lulling women into a false sense of security?
DR. ANTHONY FAUCI: First of all, Margaret, no intervention works 100 percent. But whenever you have one that works partially, you always have got to be careful that there will be a disinhibition, as we call it, namely people taking more risks because they think they’re protected.
The philosophy and the strategy of prevention is that we have to have combined prevention. Microbicides, even if it’s, in this case, 50 percent — we hope to get it up to 80 percent or more — but even if it’s partially protective, if it’s used together with other types of preventive measures, such as the use of condoms and circumcision in a male, you put them all together, it’s a package, what we call combination prevention.
MARGARET WARNER:How long will all this additional testing and the approval process take, if we’re talking about making it available in the U.S.?
DR. ANTHONY FAUCI: Well, first of all, with our regulatory authorities and the way we look at things, that we want to make sure it’s absolutely safe, because you don’t want to have the paradoxical effect of doing more harm than good.
And when you have approval of something that will be on the shelf that doctors would prescribe, you’re going to need a trial that’s much larger, with much more data. And that’s the reason why I keep getting back to saying that this is a very powerful proof of concept, but it isn’t the definitive proof that would have the FDA approve it tomorrow. That’s just not going to happen. We’re going to need more data.
MARGARET WARNER:South Africa’s health minister said today his country is considering rolling out the gel before it’s officially licensed in the U.S. What do you think about that?
DR. ANTHONY FAUCI: I think that’s — that’s something reasonable that should be respected. You know, here in this country, we have a prevalence of infection of less than 1 percent in the general population. In other populations within the United States, it’s a little bit more. But, in general, it’s very low.
If you look at southern Africa, particularly South Africa, they have close to five million cases of HIV, and they have a prevalence of around 10 percent, double digits. So, you can’t judge in a one-size-fits-all. For some countries, even something with this degree of efficacy, a health minister, such as the health minister for South Africa, and the authorities in South Africa, may make a reasonable decision to roll it out. There’s nothing wrong with that.
It has to be matched to what the situation is in the particular country involved.
MARGARET WARNER:Dr. Tony Fauci, thank you so much.
DR. ANTHONY FAUCI: Good to be here.