A new drug could be a breakthrough in the project to cure HIV, acccording to researchers.
The combination of drugs helped stave off a monkey version of HIV for nearly two years after the animals stopped receiving treatments, researchers said. Now they hope that the same solution could work for humans.
Four weeks after the rhesus macaques were given the therapy, almost no simian immunodeficiency virus (SIV) could be found in their blood or gastro-intestinal tissues. And two years later they appeared to be entirely healthy.
The treatment takes standard HIV drugs, known as antiretroviral therapy or ART, and combines them with an experimental antibody that goes for the same target as an existing drug used to treat inflammatory bowel diseases such as Crohn's and ulcerative colitis. Tweaked slightly, it was used on SIV.
A pilot trial of the effect of that drug, named vedolizumab, on HIV-infected patients has already begun in the US. Scientists hope that will show that the therapy works in the same way it did on the monkeys in the study.
"We have good reasons to believe that the therapy will work similarly in humans,” said Lutz Walter, from the German Primate Centre (DPZ) at the Leibniz Institute for Primate Research in Gottingen, who worked on the study. “It would be a breakthrough for the future treatment of HIV patients."
Unlike many other HIV breakthroughs and potential solutions, the new therapy isn’t a vaccine because it doesn’t make the body ready to defend itself against the virus. Instead, it works by helping out the immune system after infection, helping it to target white blood cells that are affected by HIV.
The therapy was based on the understanding that when HIV first infects a person, it attacks a specific kind of cell that gather together in the gut. The therapy looked to counter that effect, putting the disease into “sustained remission” or what scientists consider to be a functional cure.
"The experimental treatment regimen appears to have given the immune systems of the monkeys the necessary boost to put the virus into sustained remission," said Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious diseases, part of the NIH, who co-led the study.
The monkeys were first given a course of retroviral drugs, a standard treatment for HIV, which was later withdrawn.
Seven animals given no further treatment were quickly overwhelmed by the returning virus. Of the eight others treated with the vedolizumab variant, six experienced a rebound of viral levels which was controlled within four weeks. The remaining two saw no resurgence of infection at all.
In addition animals treated with the antibody saw a gradual restoration of helper T-cells and other immune cells that had earlier been depleted by HIV attack.
Senior author Professor Aftab Ansari, from Emory University School of Medicine and Yerkes National Primate Research Center in the US, said: "The antibody appears to have helped the entire immune system rebuild itself."
Sustained remission has been a major goal of scientists researching new HIV treatments.
Currently, most patients rapidly relapse as soon as they stop taking antiretroviral drugs. Post-treatment control of HIV has been reported in only a handful of people who were treated soon after infection.
Additional reporting by agencies
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