therapy approach that engineers a
person's T cells so that they become resistant to the human
immunodeficiency virus has shown early signs of success, researchers said.
called gene editing, the process acts like molecular scissors to snip off an
entry portal for HIV so the virus cannot enter these key immune cells.
the cells lack the CCR5 protein, the immune system behaves much the way it does
in a rare set of people – about 1% of the population – who are born with a genetic
mutation that prevents them from getting HIV.
say the development puts researchers a step closer on the path toward curing
Aids, which has infected nearly 70 million people and killed some 35
study shows that we can safely and effectively engineer an HIV patient's own T
cells to mimic a naturally occurring resistance to the virus," said senior
author Carl June of the University of Pennsylvania.
Repopulating the immune system
re-infused 12 patients with their own modified
cells and saw them persist in the body, essentially repopulating their immune
on the phase I trial results reported in the New England Journal of Medicine,
the technique was described as "generally safe".
serious adverse event was reported in a patient who was rushed to the emergency
room with fever, chills, joint pain and back pain within 24 hours of infusion.
said the problem was likely a reaction to the study drug. All patients
completed the 36-week study and are being monitored for the next 10 years.
treatment also decreased, at least temporarily, the viral loads of some
patients taken off antiretroviral drug therapy, or ART.
Infusion of 10 billion cells
patients were each given a single infusion of about 10 billion cells between
May 2009 and July 2012.
dramatic spike in modified T cells was seen in the patients' bodies a week
after the infusion.
people were taken off ART for up to 12 weeks, beginning four weeks after
infusion, and the other six patients remained on treatment.
of the patients who stopped ART saw their viral loads drop.
patient's viral load dropped so low that it became undetectable. Researchers
later discovered the person had inherited the CCR5 delta-32 gene mutation from
one parent, essentially giving the patient a head start on the treatment.Step towards a cure
on the study came from the Albert Einstein College of Medicine and Sangamo
BioSciences, which developed approach for editing the cells, known as zinc
finger nuclease (ZFN) technology.
said he hopes that modified T cells, an experimental approach that has also
shown promise against some forms of leukaemia,
could one day lead to a functional cure for HIV/Aids and eliminate the need for
far, only one man – American Timothy Brown, often called the Berlin patient –
has been cautiously considered cured of HIV after undergoing a bone marrow
transplant from a donor with a natural genetic mutation against HIV. He has
been off ART since 2008.
have been trying for years to find a way to replicate those results for the
wider population, in a way that might be safer than a risky bone marrow
transplant, which carries a 30% risk of death.
the road to a cure is still long, experts praised the research for making
gene therapy were found to be a way to cure HIV, I really do believe that
somebody is going to come up with a way that it could be delivered,"
Rowena Johnston, vice president and director of research at The Foundation for
Aids Research, or amfAR, told AFP.
Fauci, director of the National Institute of Allergy and Infectious Diseases,
which contributed funding to the research, described it as "clearly
you have got to be careful that you don't at this point declare any victory
because we are still far from any widespread applicability," Fauci said.
Gene therapy for HIV inches forward
therapy shows promise in reducing HIV