Strategy gives hope for HIV vaccine
Drugs holidays may strengthen the immune system
By Charlene Laino
MSNBC
Sept. 27 — Could giving AIDS patients a “drug holiday” boost their immune systems, preventing HIV from wreaking its ravaging toll on the body? Preliminary studies suggest so. The strategy, in which patients are taken off their medication for weeks, even months, at a time, may not only allow some people to quit drugs altogether, but may lead to the development of a vaccine to treat infected people, researchers said Wednesday.
AT THE SAME time, doctors warned, the strategy is still a gamble and AIDS patients should not take themselves off their medication without talking to their physicians.
In a new study, five patients started on aggressive anti-AIDS therapy very soon after they were infected with HIV were able to stay off drugs for months after one or two drug holidays, Boston researchers reported in the journal Nature.
“We want to deliver two messages with this report: that diagnosing HIV infection and beginning antiviral treatment as early as possible can make a fundamental difference in the way the immune system handles the virus, and that HIV treatment strategies based on the immune system — including vaccines — appear to have great potential,” said study author Dr. Bruce Walker of Massachusetts General Hospital and Harvard Medical School.
“We also want to stress that persons currently taking the anti-HIV drug ****tail referred to as HAART [highly active antiretroviral therapy] should continue taking their drugs,” he added.
To date, only patients who began antiviral treatment during acute infection — flu-like symptoms that appear within weeks of exposure to virus — have been studied, Walker noted. Trials in people who first start HAART six months or more after infection — the majority of infected persons — are yet to be done.
Dr. Franco Lori of the Research Institute for Genetic and Human Therapy in Washington, D.C., and Pavia, Italy, embraced the work, noting that preliminary evidence suggests that immune control of HIV may be a more realistic alternative than the elusive goal of eradicating HIV with potent, but often toxic, drug ****tails.
DEVELOPING A VACCINE
What excites Walker most is the idea that these studies could lead to a therapeutic vaccine — one that could be used to treat patients who are already infected with HIV, as opposed to one to prevent the disease in unexposed individuals.
Walker said he believed the first course of HAART helped the immune system recover enough to attack the virus when the drugs were stopped. Both “helper” T-cells and “killer” T-cells came back and fought the virus.
A vaccine might work in the same way.
HIV leaves the body depleted of the very immune cells — the “helper” T-cells and “killer” T-cells — that the body needs to fight infection. Unchecked, it simply wipes them out, leaving the body vulnerable to other germs.
But when HAART is started right away, the immune system has a chance to muster its forces, producing significant levels of HIV-specific T-cells that seem necessary to keep the virus in check.
Then, when one stops taking the medication, a little virus comes back. This, in turn, primes the already strengthened immune system to build antibodies and further fight the virus — just like a vaccine.
STUDY RESULTS
For the new study, Walker’s team prescribed HAART to eight patients who had been diagnosed within three days of being infected with HIV. Once the level of virus in their blood had dropped to levels undetectable by standard screening, the patients were taken off the drugs.
Two patients have never had to go back on HAART. One restarted the drugs even though his viral levels were low but then came off HAART again, while five saw their virus come back badly enough to where they had to go back on HAART.
All five were given a second drug holiday. This time, only one had to restart HAART because of rising virus levels. Two others chose to resume treatment even though their viral load remained low.
In all, five of the eight remain off therapy an average of 2.7 years after initial infection, Walker reported.
Both Lori and Walker worried about sending the wrong message — that is, that patients should take themselves on and off therapy. An important concern is that drug-resistant strains of the virus may develop in some patients. Another fear is that breaks in therapy could increase the risk of side effects, such as nausea and bone loss, that often are worse when patients first start drugs and decrease as their bodies become accustomed to the medications.
“Clearly we need more patients, clearly we need more studies ... but this gives us a ballpark level of these responses to shoot for, and we think this gives us something to consider for a vaccine,” Walker said.
“Even if the viral loads on these patients rise tomorrow, we’ve shown that it is possible for the immune system to suppress HIV, something many believed could not be done,” Walker says. “Not only does this result open the door to investigating [vaccines] for HIV, but the same strategy also may be applied to other chronic viral infections, like hepatitis C, that currently escape immune system control.”
----------------------------
I never wanted anything, the way I wanted you that night. My love transcended space and time. I never wanted anything, the way I wanted you. - Bif Naked
Drugs holidays may strengthen the immune system
By Charlene Laino
MSNBC
Sept. 27 — Could giving AIDS patients a “drug holiday” boost their immune systems, preventing HIV from wreaking its ravaging toll on the body? Preliminary studies suggest so. The strategy, in which patients are taken off their medication for weeks, even months, at a time, may not only allow some people to quit drugs altogether, but may lead to the development of a vaccine to treat infected people, researchers said Wednesday.
AT THE SAME time, doctors warned, the strategy is still a gamble and AIDS patients should not take themselves off their medication without talking to their physicians.
In a new study, five patients started on aggressive anti-AIDS therapy very soon after they were infected with HIV were able to stay off drugs for months after one or two drug holidays, Boston researchers reported in the journal Nature.
“We want to deliver two messages with this report: that diagnosing HIV infection and beginning antiviral treatment as early as possible can make a fundamental difference in the way the immune system handles the virus, and that HIV treatment strategies based on the immune system — including vaccines — appear to have great potential,” said study author Dr. Bruce Walker of Massachusetts General Hospital and Harvard Medical School.
“We also want to stress that persons currently taking the anti-HIV drug ****tail referred to as HAART [highly active antiretroviral therapy] should continue taking their drugs,” he added.
To date, only patients who began antiviral treatment during acute infection — flu-like symptoms that appear within weeks of exposure to virus — have been studied, Walker noted. Trials in people who first start HAART six months or more after infection — the majority of infected persons — are yet to be done.
Dr. Franco Lori of the Research Institute for Genetic and Human Therapy in Washington, D.C., and Pavia, Italy, embraced the work, noting that preliminary evidence suggests that immune control of HIV may be a more realistic alternative than the elusive goal of eradicating HIV with potent, but often toxic, drug ****tails.
DEVELOPING A VACCINE
What excites Walker most is the idea that these studies could lead to a therapeutic vaccine — one that could be used to treat patients who are already infected with HIV, as opposed to one to prevent the disease in unexposed individuals.
Walker said he believed the first course of HAART helped the immune system recover enough to attack the virus when the drugs were stopped. Both “helper” T-cells and “killer” T-cells came back and fought the virus.
A vaccine might work in the same way.
HIV leaves the body depleted of the very immune cells — the “helper” T-cells and “killer” T-cells — that the body needs to fight infection. Unchecked, it simply wipes them out, leaving the body vulnerable to other germs.
But when HAART is started right away, the immune system has a chance to muster its forces, producing significant levels of HIV-specific T-cells that seem necessary to keep the virus in check.
Then, when one stops taking the medication, a little virus comes back. This, in turn, primes the already strengthened immune system to build antibodies and further fight the virus — just like a vaccine.
STUDY RESULTS
For the new study, Walker’s team prescribed HAART to eight patients who had been diagnosed within three days of being infected with HIV. Once the level of virus in their blood had dropped to levels undetectable by standard screening, the patients were taken off the drugs.
Two patients have never had to go back on HAART. One restarted the drugs even though his viral levels were low but then came off HAART again, while five saw their virus come back badly enough to where they had to go back on HAART.
All five were given a second drug holiday. This time, only one had to restart HAART because of rising virus levels. Two others chose to resume treatment even though their viral load remained low.
In all, five of the eight remain off therapy an average of 2.7 years after initial infection, Walker reported.
Both Lori and Walker worried about sending the wrong message — that is, that patients should take themselves on and off therapy. An important concern is that drug-resistant strains of the virus may develop in some patients. Another fear is that breaks in therapy could increase the risk of side effects, such as nausea and bone loss, that often are worse when patients first start drugs and decrease as their bodies become accustomed to the medications.
“Clearly we need more patients, clearly we need more studies ... but this gives us a ballpark level of these responses to shoot for, and we think this gives us something to consider for a vaccine,” Walker said.
“Even if the viral loads on these patients rise tomorrow, we’ve shown that it is possible for the immune system to suppress HIV, something many believed could not be done,” Walker says. “Not only does this result open the door to investigating [vaccines] for HIV, but the same strategy also may be applied to other chronic viral infections, like hepatitis C, that currently escape immune system control.”
----------------------------
I never wanted anything, the way I wanted you that night. My love transcended space and time. I never wanted anything, the way I wanted you. - Bif Naked