News on HIV/AIDS
Expert: Better HIV Drugs Won't Cure AIDS
Progress, Problems With New Drugs and Vaccines Revealed at Conference
By Daniel DeNoon
July 11, 2002 -- At each AIDS conference it's the same. Everyone hopes to hear about the magic bullet that will end the most terrible plague ever to visit mankind. This year's XIV International AIDS Conference may put an end to all that. The bottom line: no magic bullet now, or ever.
That's the reality check offered by Johns Hopkins University's Robert Siliciano, MD, PhD. In a sobering presentation, Siliciano made it clear that no drug will ever cure a person of HIV infection. The hope that remains is that new drugs and new immune-based treatments can keep HIV-infected people AIDS-free for the rest of their lives.
Indeed, the conference was filled with encouraging progress reports on badly needed new drugs -- and, even better, new types of drugs. Perhaps the best example of this is the progress of T-20, a new type of drug that keeps HIV from infecting new cells. Clinical trials show the drug can be of great benefit to people for whom several other AIDS drugs no longer work. Most observers expect that FDA approval will come soon. The downside: the drug must be taken by injection, and a complex manufacturing process almost ensures that it will be very, very expensive.
"Expensive" has been a key word at this year's conference. No matter how good AIDS drugs get, they can't help people who can't afford them. About half a million people have access to these treatments. That leaves about 35.5 million of the world's HIV-infected people with no hope in sight. The conference had no shortage of pleas for care, demands for cash, and plans for action. Whether the world's economic and political leaders will lend an ear -- and a helping hand -- remains to be seen.
An AIDS vaccine remains the world's best hope for an end to the epidemic. This year's conference featured a big media splash by VaxGen, the firm that makes the experimental AIDS vaccine nearing the end of large-scale tests. The moving spirit behind this vaccine is Donald P. Francis, MD, a hero of the early days of the AIDS epidemic. Most vaccine researchers doubt that the relatively simple VaxGen vaccine will work very well. Francis has relentlessly pushed for trials, reasoning that you can't succeed if you don't try. VaxGen has made the rather premature announcement that it is ready to begin large-scale vaccine production. Results of the trial won't be known until early 2003.
Stunning bad news on the vaccine front came from Harvard's Bruce Walker, MD. Based on results in monkey experiments, the most promising crop of AIDS vaccines are those that induce virus-fighting T cells. Walker is an expert on these cells. According to an article by Laurie Garrett in Newsday, Walker reported on a patient who began effective drug treatment very soon after becoming infected with HIV. This patient developed very strong T-cell immune responses that kept the virus in check, even when he stopped taking anti-HIV drugs. But this strong T-cell immunity didn't keep him from getting a second HIV infection. It didn't even keep the new infection from making him very sick. That's very bad news for vaccines. It remains to be seen whether this finding has broad-reaching implications, or whether it's just a scientific oddity.
Better vaccine news came from several presentations. The most intriguing is a report by Julianna Lisziewicz, MD, co-director of Georgetown University's Research Institute for Genetic and Human Therapy. Lisziewicz and colleagues have developed a therapeutic DNA vaccine -- they call it DermaVir -- that can be applied directly to the skin. The vaccine prolonged the lives of monkeys infected with a monkey AIDS virus.
There was plenty of new-drug news. As reported from the conference by William A. O'Brien, MD, for WebMD Medscape, highlights included:
Fos-amprenavir is a new version of the protease inhibitor Agenerase. It's much easier to take and may be approved by the end of 2002.
MIV 301 was discovered 14 years ago but abandoned because of severe bone marrow toxicity. Now it turns out the drug is highly effective against HIV resistant to other nucleoside-based anti-HIV drugs such as AZT.
DPC817 and ACH-126,443 are two different drugs from two different companies that are mirror images of each other. They differ in activity and toxicity, but they are both active against drug-resistant HIV.
Capravirine (AG1549), a non-nucleoside reverse transcriptase inhibitor (NNRTI) that was on hold because it was toxic in dog studies. Now, it appears, it doesn't harm humans.
SCH-C keeps HIV from getting into cells by the CCR5 entryway. Early trials showed that it might cause heart problems. Now there's SCH-D, a more active version.
PRO 542 and the more recent PRO 140 are manmade antibodies that keep HIV from catching hold of cells. These agents have antiviral activity that continues or increases during the week after short-term administration is discontinued.
AMD-070 keeps HIV from getting into cells through the CXCR4 entryway.
L-870812 and L-870810 are part of a new generation of drugs that block integrase. That's the substance HIV uses to stick its genetic code into the DNA of human cells. Right now there aren't any approved integrase inhibitors, so a new class of drugs would be a big help. What's more, HIV that becomes resistant to integrase inhibitors seems to be greatly weakened.
S-1360, another integrase inhibitor, was shown to be well tolerated in 18 healthy volunteers. Trials will continue, likely with once-daily dosing.
Progress, Problems With New Drugs and Vaccines Revealed at Conference
By Daniel DeNoon
July 11, 2002 -- At each AIDS conference it's the same. Everyone hopes to hear about the magic bullet that will end the most terrible plague ever to visit mankind. This year's XIV International AIDS Conference may put an end to all that. The bottom line: no magic bullet now, or ever.
That's the reality check offered by Johns Hopkins University's Robert Siliciano, MD, PhD. In a sobering presentation, Siliciano made it clear that no drug will ever cure a person of HIV infection. The hope that remains is that new drugs and new immune-based treatments can keep HIV-infected people AIDS-free for the rest of their lives.
Indeed, the conference was filled with encouraging progress reports on badly needed new drugs -- and, even better, new types of drugs. Perhaps the best example of this is the progress of T-20, a new type of drug that keeps HIV from infecting new cells. Clinical trials show the drug can be of great benefit to people for whom several other AIDS drugs no longer work. Most observers expect that FDA approval will come soon. The downside: the drug must be taken by injection, and a complex manufacturing process almost ensures that it will be very, very expensive.
"Expensive" has been a key word at this year's conference. No matter how good AIDS drugs get, they can't help people who can't afford them. About half a million people have access to these treatments. That leaves about 35.5 million of the world's HIV-infected people with no hope in sight. The conference had no shortage of pleas for care, demands for cash, and plans for action. Whether the world's economic and political leaders will lend an ear -- and a helping hand -- remains to be seen.
An AIDS vaccine remains the world's best hope for an end to the epidemic. This year's conference featured a big media splash by VaxGen, the firm that makes the experimental AIDS vaccine nearing the end of large-scale tests. The moving spirit behind this vaccine is Donald P. Francis, MD, a hero of the early days of the AIDS epidemic. Most vaccine researchers doubt that the relatively simple VaxGen vaccine will work very well. Francis has relentlessly pushed for trials, reasoning that you can't succeed if you don't try. VaxGen has made the rather premature announcement that it is ready to begin large-scale vaccine production. Results of the trial won't be known until early 2003.
Stunning bad news on the vaccine front came from Harvard's Bruce Walker, MD. Based on results in monkey experiments, the most promising crop of AIDS vaccines are those that induce virus-fighting T cells. Walker is an expert on these cells. According to an article by Laurie Garrett in Newsday, Walker reported on a patient who began effective drug treatment very soon after becoming infected with HIV. This patient developed very strong T-cell immune responses that kept the virus in check, even when he stopped taking anti-HIV drugs. But this strong T-cell immunity didn't keep him from getting a second HIV infection. It didn't even keep the new infection from making him very sick. That's very bad news for vaccines. It remains to be seen whether this finding has broad-reaching implications, or whether it's just a scientific oddity.
Better vaccine news came from several presentations. The most intriguing is a report by Julianna Lisziewicz, MD, co-director of Georgetown University's Research Institute for Genetic and Human Therapy. Lisziewicz and colleagues have developed a therapeutic DNA vaccine -- they call it DermaVir -- that can be applied directly to the skin. The vaccine prolonged the lives of monkeys infected with a monkey AIDS virus.
There was plenty of new-drug news. As reported from the conference by William A. O'Brien, MD, for WebMD Medscape, highlights included:
Fos-amprenavir is a new version of the protease inhibitor Agenerase. It's much easier to take and may be approved by the end of 2002.
MIV 301 was discovered 14 years ago but abandoned because of severe bone marrow toxicity. Now it turns out the drug is highly effective against HIV resistant to other nucleoside-based anti-HIV drugs such as AZT.
DPC817 and ACH-126,443 are two different drugs from two different companies that are mirror images of each other. They differ in activity and toxicity, but they are both active against drug-resistant HIV.
Capravirine (AG1549), a non-nucleoside reverse transcriptase inhibitor (NNRTI) that was on hold because it was toxic in dog studies. Now, it appears, it doesn't harm humans.
SCH-C keeps HIV from getting into cells by the CCR5 entryway. Early trials showed that it might cause heart problems. Now there's SCH-D, a more active version.
PRO 542 and the more recent PRO 140 are manmade antibodies that keep HIV from catching hold of cells. These agents have antiviral activity that continues or increases during the week after short-term administration is discontinued.
AMD-070 keeps HIV from getting into cells through the CXCR4 entryway.
L-870812 and L-870810 are part of a new generation of drugs that block integrase. That's the substance HIV uses to stick its genetic code into the DNA of human cells. Right now there aren't any approved integrase inhibitors, so a new class of drugs would be a big help. What's more, HIV that becomes resistant to integrase inhibitors seems to be greatly weakened.
S-1360, another integrase inhibitor, was shown to be well tolerated in 18 healthy volunteers. Trials will continue, likely with once-daily dosing.