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| Ten years after the first confirmed case of an HIV-infected person being rid of the deadly disease, a man known only as the 'London patient' has shown no sign of the virus for nearly 19 months |
For just the second time ever an HIV patient is in sustained remission from the virus in what was hailed by experts Tuesday as proof that the AIDS-causing condition could one day be curable.
Ten years
almost to the day since the first confirmed case of an HIV-infected person
being rid of the deadly disease, a man known only as the "London
patient" has shown no sign of the virus for nearly 19 months, doctors
reported in the journal Nature.
Both
patients underwent bone marrow transplants to treat blood cancers, receiving
stem cells from donors with a genetic mutation present in less than one percent
of Europeans that prevents HIV from taking hold.
"It is
a landmark. After 10 years of not being able to replicate (the first case),
people were wondering if this was a fluke," said lead author Ravindra Gupta,
a professor at the University of Cambridge.
"I
think it is important to reaffirm that this is real and it can be done,"
Gupta told AFP.
The
findings will be presented later Tuesday at a medical conference in Seattle,
Washington.
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Graphic on
how HIV attacks white blood cells
|
Millions of
people infected with HIV around the globe keep the disease in check with
so-called antiretroviral therapy (ARV), but the treatment does not rid patients
of the virus.
Close to 37
million people are living with HIV worldwide, but only 59 percent are receiving
ARV. Nearly one million people die every year from HIV-related causes.
A new
drug-resistant form of HIV is also a growing concern.
The first
sustained remission survivor, announced in 2009 as "the Berlin
patient" and later named as American Timothy Brown, was given two
transplants and underwent total body irradiation to treat leukaemia -- a
process that nearly killed him.
Gupta said
that while a second successful transplant did not constitute a generalised
cure, it showed that even milder forms of treatment can achieve full remission.
"There
are a number of learning points here," he said. "Radiation has a lot
of side-effects and leads to a delayed recovery of the bone marrow, so it's
really good that we've shown you don't need radiation.
"The
Berlin patient also had two rounds of chemotherapy because the first one didn't
work. We've done ours just once, and it was also a milder form, which is
important," he added.
 |
Close to 37
million people are living with HIV worldwide, but only 59 percent
are receiving
treatment
|
'HIV is
curable'
Both
patients received stem cell transplants from donors carrying a genetic mutation
that prevents expression of an HIV receptor, known as CCR5.
The London
patient was diagnosed with HIV infection in 2003 and had been on antiretroviral
therapy since 2012.
Later that
year, he was diagnosed with advanced Hodgkin's Lymphoma, a deadly cancer.
He
underwent a stem cell transplant in 2016 from a donor with two copies of a CCR5
gene variant, which is resistant to most HIV-1 virus strains.
"CCR5
is something essential for the virus to complete its life-cycle and we can't
knock out many other things without causing harm to the patient," said
Gupta.
"We
know that CCR5 can be knocked out without any serious consequences because
people are walking around without that gene."
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Map showing
the latest data on HIV infections for adults between 2010 to 2017
|
CCR5 was
the target in the genome of the controversial gene-edited twins born last year
in China, whose father is HIV-positive.
Experts
cautiously welcomed Tuesday's announcement.
The
International AIDS Society said in a statement Tuesday that results from the
second patient "reaffirm our belief that there exists a proof of concept
that HIV is curable".
Sharon
Lewin, director of the Peter Doherty Institute for Infection and Immunity, told
AFP that the second case showed a cure was "feasible".
"We
can try to tease out which part of the transplant might have made a difference
here, and allowed this man to stop his anti-viral drugs," she added.
New
communities
After the
bone marrow transplant, the London patient remained on ARV for 16 months, at
which point treatment was stopped.
Regular
testing has confirmed that the patient's viral load remained undetectable since
then.
But
scientists were keen to stress that the technique is likely only viable among a
tiny percentage of sufferers.
 |
The first
sustained remission survivor, announced in 2009 as "the Berlin
patient" and
later named as American Timothy Brown, was given two
transplants and underwent
total body irradiation to treat leukaemia -- a
process that nearly killed him
|
"Due
to the rarity of suitable donors, this precise approach will not be available
to all HIV patients," said Aine McKnight, professor of Viral Pathology at
Queen Mary University, London.
"However,
this work has the potential to stimulate research into more generally applicable
therapies."
Gupta said
he hoped to expand research on the stem-cell transplant technique to focus on
communities in Africa, where the HIV-beating mutation does not naturally occur.
"Expanding
remission to populations that are affected disproportionately is quite
important," he told AFP.
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