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emergency post 07,June 2019 (1) (464)

Leukaemia drug offers hope of an HIV cure to replace the 'dangerous' stem cell transplant

Leukaemia drug offers hope of an HIV cure to replace the 'dangerous' stem cell transplant
A leukaemia drug may completely rid HIV-positive patients of the virus that slowly leads to AIDS, scientists claim.

Trials on four infected monkeys showed two given arsenic trioxide had no detectable levels of the virus 80 days after treatment.The other two had a diminished pool of the virus inside their bodies - but not enough to be technically classed as in remission.None of the macaques - given a strain of HIV similar to that which strikes humans - were taking other drugs designed to keep the virus at bay.

Experts hope the breakthrough could lead to ways of curing the 37million people living across the world who are known to have the virus. Charities say it may lead to a way of replacing a risky procedure that simultaneously fights cancer and has already rid two patients of the virus. But they warned the macaque study, which they described as 'promising', is still preliminary and needs to be further investigated.

UNICEF’s HIV/AIDS advisor Shaffiq Essajee told MailOnline: 'Findings from the recent study are very exciting and suggest that new drugs, in combination with existing antiretrovirals, may be able to reduce or eliminate the HIV reservoir.'These results warrant further research to assess the safety and efficacy of this approach for people with HIV especially children.'

Doctors are currently experimenting with a stem-cell transplant that has rid at least two patients of the virus long-term. It is known to be dangerous.Details of the most recent patient - known as the 'London patient' - were only made public in March at a medical conference in Seattle. The patient, who had Hodgkin lymphoma, had the last-ditch stem cell transplant from a donor with a HIV-resistant gene.After 18 months, the man showed no signs of HIV – despite choosing not to take the antiretroviral drugs (ART) to keep his virus at bay.

ART, taken daily, suppresses the virus to prevent a resurgence. Within six months of taking the pills, the virus can be quashed to undetectable levels.A few weeks off the pills and patients' levels of the virus can skyrocket.The man is not considered to be cured – only in long-term remission. For example, cancer patients have to be in remission for five years before being labelled as cured. However, the experimental procedure - which works by giving patients genes from people who are naturally immune to HIV - is dangerous because patients can suffer a fatal reaction if substitute immune cells don't take. Critics also say it doesn't apply to most people living with HIV because it may only benefit a handful of patients who also have cancer.The new approach, involving a drug already approved in the US and Europe, could be used, or lead to a substitute to the risky stem cell procedure - that also works on patients who don't already have cancer.

Researchers at King's College London and the Chinese Academy of Sciences gave four HIV-positive macaques arsenic trioxide.Two of the monkeys showed signs of the virus being fully suppressed, according to the report published in the journal Advanced Science.Neither experienced a 'rebound' – when the virus becomes detectable again – when all their antiretroviral therapies were stopped.The other two showed signs of harbouring a lower amount of the virus but not enough to prevent a rebound, according to the results.

The researchers, led by Dr Qing Yang, showed the drug approach can mimic the second phase of the risky stem cell transplant.Phase two works by reducing the number of immune cells that have HIV receptors on. However, it is unclear how arsenic trioxide does this.In transplants, patients receive stem cells from people with a mutated CCR5 gene, which causes their white blood cells to have incomplete receptors, blocking the HIV virus from entering and infecting cells. CCR5 is the gene that HIV targets and uses as its access point to enter the immune system.Further trials are needed to confirm the new findings before the drug is tested on humans.

Researchers first proved arsenic trioxide can replicate phase one of the stem cell treatment more than a decade ago, but on a milder scale.In laboratory tests, they discovered it could kill the immune cells harbouring HIV without affecting cells that are free of the virus.

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