Written By: Nirmalya Dutta | Updated : March 10, 2014 11:10 PM IST
A single injection of an experimental drug may someday protect people from infection with the AIDS virus for up to three months, a US study said on Tuesday. The study, published in the US journal Science, showed that the drug called GSK 744LA can protect macaque monkeys from repeated intrarectal infections with the deadly SHIV, a hybrid between the human and monkey AIDS virus, Xinhua reported.
The efficacy and safety of the drug have not been tested in humans, but David Ho, whose team at the Aaron Diamond AIDS Research Centre in New York led the study, the drug may be maintained at adequate level for about three of four months in humans. 'Therefore, we believe the drug should be given once every quarter,' said Ho, noting that their results 'give a big momentum boost to this HIV prevention effort'.
In the new study, the researchers gave two injections of the drug to eight macaques and then 'challenged' the animals by putting SHIV into their rectums once a week. They found none of the animals became infected after eight challenges. In a second experiment, SHIV readily infected eight untreated control monkeys.
This novel approach was based on the proven strategy of protecting people who do not have HIV but are at high risk for infection with antiretroviral pills known as oral pre-exposure prophylaxis (PrEP). 'It has been shown already that taking anti-HIV medications once a day... could protect high-risk individuals from catching HIV. However, in such an approach, most persons cannot follow the prescribed regimen with good compliance/adherence,' said Ho.
'With long-acting drug like 744LA, we take away this adherence problem, with the expectation that protection results would be better,' he said. Robert Grant, a virologist at the University of California, San Francisco (UCSF), who was not involved in the study, believed that the new study 'would be a game changer'.
'This is the most exciting thing happening that I know of in HIV prevention studies today,' Grant, a pioneer of oral PrEP studies in humans, told the Science journal. Philip Johnson of the Children's Hospital of Philadelphia in Pennsylvania, however, questioned the compliance. 'This is going to require multiple injections over the lifetime of an individual,' Johnson told Science. 'How feasible is it truly in the long term? '
Ho said while HIV vaccines that protect are 'still far far away', their approach could be used in the interim period before a protective vaccine is developed. He said their next step is to proceed, together with drugmaker GlaxoSmithKline, to conduct human trials. 'We will soon begin a phase-2 human trial of 744LA in the US. It is anticipated that we will obtain more data, including more safety information, on this long-acting drug within the next year,' he said. 'We are now in discussion with the company on how to ultimately proceed with clinical trials to test the protective efficacy of 744LA in high risk populations throughout the world, including in gay men in China where HIV infection rates are very high.'
Other possible HIV cures
Should we be optimistic or cautious? This isn't the first time that we've been presented with tales that an HIV cure is on its way. The most famous of them are:
The Berlin Patient Case Leukaemia
For a long time researchers believed there was no cure. Even five years ago, a scientist who wanted to work on HIV cure research was laughed at. But all that changed with Timothy Brown aka the Berlin Patient. Brown an HIV-positive man who developed leukaemia. After first-line cancer treatments failed, a bone marrow transplant procedure was done. Two transplants later, not only was his leukaemia in remission, his immune system actually managed to ward off HIV. Brown no longer takes antiretroviral drugs or tests positive for HIV. Essentially, he was cured. Read more
Bee venom to cure HIV?
A study suggested that bee venom might have the potency to kill the human immunodeficiency virus (HIV). Researchers at the Washington University School of Medicine had demonstrated that a toxin called melittin which is found in bee venom is the reason for this. The researchers used nanoparticle technology to target the virus. Particles smaller than HIV were infused with bee venom and since HIV cells are smaller than normal body cells the nanoparticles only targeted HIV.
'Melittin on the nanoparticles fuses with the viral envelope,' said research instructor Joshua L. Hood, MD, PhD. 'The melittin forms little pore-like attack complexes and ruptures the envelope, stripping it off the virus.' Adding, 'We are attacking an inherent physical property of HIV. Theoretically, there isn't any way for the virus to adapt to that. The virus has to have a protective coat, a double-layered membrane that covers the virus.'
Stem cell therapy to overcome HIV?
In a path-breaking breakthrough two American were believed to have overcome HIV after undergoing stem-cell therapy! The news has met with widespread elation with experts believing that a cure might be on the cards. Doctors from the Brigham and Women's Hospital in Boston announced on Wednesday night that two previously HIV-positive patients no longer had detectable virus levels in their blood or tissue after having bone marrow stem-cell transplants to treat cancer between two and four years ago, the Age reported. (Read more )
Aggressive antiretroviral treatment the Mississippi baby case
There were reports in March 2013 of a toddler who was completely cured of the virus after being born of it. She has been cured of the disease after following an aggressive regime of drugs. This was the second documented case of a person being completely cured of the virus after an adult known as the Berlin Patient was cured as a result of bone-marrow transplant. This startling piece of information was discovered when the baby's mother stopped treatment and doctors lost track of the baby who was given a bout of heavy drugs (current procedure suggests only a modest daily dose of antiretroviral treatment) about 30 hours after she was born at a rural Mississippi hospital, doctors said at a medical meeting in Atlanta. However, a doctor poured cold water on cold water on what was termed 'the greatest medical breakthrough of the century'.
In his piece, Dr Siedner pointed out in his column, exposure to HIV doesn't mean that the baby will have HIV. 'We will likely never know if those cells were from the child or maternal cell that has been transmitted during pregnancy or birth.' When a child is born, he or she has some maternal cells in his system so it's impossible to tell whether the child actually had HIV or not, or the tests detected the maternal HIV positive cells.
The MX2 gene
According to a study published in the journal Nature, scientists have discovered a new gene which can inhibit the HIV virus from spreading after it has entered the body. The study was led by Dr Caroline Goujon and Professor Mike Malim at the Department of Infectious Diseases, King's College London. It was conducted by introducing the virus to two separate lines of human cells. On one line, they introduced the MX2 gene along with the virus, while on the other they didn't. The line on which the MX2 gene was introduced, it was seen that the virus had stopped replicating. (Read more.)
With inputs from IANS
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