London
patient cured of HIV-AIDS in medical breakthrough
A second person is in sustained remission from HIV-1, the
virus that causes AIDS, after ceasing treatment and is likely cured,
researchers were set to announce at a medical conference Tuesday.
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, they reported in
the journal Nature.
Both patients had received bone marrow transplants to treat
blood cancers, receiving stem cells from donors with a rare genetic mutation
that prevents HIV from taking hold.
“By achieving remission in a second patient using a similar
approach, we have shown that the Berlin patient was not an anomaly,” said lead
author Ravindra Gupta, a professor at the University of Cambridge, referring to
the first known functional cure.
Millions of people infected with HIV around the world keep
the disease in check with so-called antiretroviral therapy (ARV), but the
treatment does not rid patients of the virus.
“At the moment, the only way to treat HIV is with
medications that suppress the virus, which people need to take for their entire
lives,” said Gupta.
“This poses a particular challenge in developing countries,”
where millions are still not receiving adequate treatment, he added.
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.
Gupta and his team emphasised that bone marrow transplant —
a dangerous and painful procedure — is not a viable option for HIV treatment.
But a second case of remission and likely cure following
such a transplant will help scientists narrow the range of treatment
strategies, he and others said.
Both the London and Berlin patients received stem cell
transplants from donors carrying a genetic mutation that prevents expression of
an HIV receptor, known as CCR5.
“Finding a way to eliminate the virus entirely is an urgent
global priority, but is particularly difficult because the virus integrates
into the white blood cells of its host,” Gupta explained.
The study describes an anonymous male patient in Britain who
was diagnosed with HIV infection in 2003 and has been on antiretroviral therapy
since 2012.
Later that year, he was diagnosed with advanced Hodgkin’s
Lymphoma, a deadly cancer.
He underwent a so-called haematopoietic stem cell transplant
in 2016 from a donor with two copies of a CCR5 gene variant, a combination
carried by about one percent of the world population.
CCR5 is the most commonly used receptor by HIV-1.
People who have two mutated copies of CCR5 are resistant to
most HIV-1 virus strains, frustrating the virus’ attempts to enter host cells.
As with cancer, chemotherapy can be effective against HIV as
it kills cells that are dividing.
But replacing immune cells with those that do not have the
CCR5 receptor appears to be key in preventing HIV from rebounding after the
treatment.
After the bone marrow transplant, the London patient
remained on ARV for 16 months, at which point ARV treatment was stopped.
Regular testing has confirmed that the patient’s viral load
remained undetectable since then.
The Berlin patient — treated for leukaemia — was given two
transplants, and underwent total body irradiation, while the British patient
received just one transplant and less intensive chemotherapy.
The research team is presenting the findings at the annual
Conference on Retroviruses and Opportunistic Infections (CROI) in Seattle,
Washington.
“The second case strengthens the idea that a cure is feasible,”
Sharon R Lewin, director of the Peter Doherty Institute for Infection and
Immunity and the University of Melbourne, told AFP.
“A bone-marrow transplantation as a cure is not viable. But
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.” (NAN)