ARV
At
the International AIDS Conference, researchers have been keeping their
focus on a new vaginal ring aimed at keeping women safe.
“Because
this product is designed to be replaced once a month, it offers
potential to increase the chances that women will continually use the
product as opposed to a product that has to be applied in a behaviorally
dependent prior to sex way or on a daily basis,” explained Dr. Carl
Dieffenbach, with the U.S. National Institutes of Health.
About 3,500 African women have signed up to take part in the study and hopes are high.
Researchers
say giving women tools to protect themselves, without having to rely on
their partner, is critical. Half of the more than 34 million people
living with HIV, the virus that causes AIDS, are women. That percentage
rises even higher in hard-hit Africa.
Scientists
in the United States yesterday said they had used a cancer drug to
flush out the AIDS virus lurking dormant in trial patients’ white blood
cells — a tentative step towards a cure.
The
ability of the HIV genome, or reproductive code, to hide out in cells
and be revived after decades poses a major obstacle in the quest for a
cure.
Being
able to expose the virus in its hiding place would allow scientists to
target the host white blood cells in a killing blitz.
“It
is the beginning of work toward a cure for AIDS,” David Margolis,
co-author of the study published in the journal Nature, told AFP as the
International AIDS Conference was under way in Washington.
HIV
is a retrovirus, inserting its DNA into the genome of host white blood
cells, CD4+T cells in this case, and turning them into virus factories.
Sometimes it goes into hiding in some cells even as others keep on
producing.
Some
34 million people around the world are living with HIV, which destroys
the immune system and has caused about 30 million AIDS-related deaths
since the disease first emerged in the early 1980s.
In
the latest study, researchers in the United States used the chemotherapy
drug vorinostat to revive and so unmask latent HIV in the CD4+T cells
of eight trial patients.
The
patients were also on antiretroviral drugs, which stops HIV from
multiplying but have to be taken for life because they do not kill the
virus hidden away in reservoirs.
“After
a single dose of the drug, at least for a moment in time, (vorinostat)
is flushing the virus out of hiding,” Margolis said of the trial results
— the first drug ever shown to do so.
“This
is proof of the concept, of the idea that the virus can be specifically
targeted in a patient by a drug, and essentially opens up the way for
this class of drugs to be studied for use in this way.”
The drug targets an enzyme that allows the virus to lie latent.
The
researchers cautioned that vorinostat may have some toxic effects and
stressed this was merely an early indication of feasibility that had to
be explored further.
Exactly what would happen after the virus was unveiled in reservoir cells was also not certain, said Margolis.
“We
know that many cells that produce HIV die in the process. We know many
cells that produce HIV can be identified and killed by the immune
system. As far as we can tell, all the viruses floating around while
patients are taking therapy don’t get into cells because they are
blocked by the therapy,” he said.
Without a host cell, the virus would die within a few minutes.
“There
is a possibility that this could work. But ... if it is only 99 percent
true and one percent of the virus escapes, it won’t succeed. That is
why we have to be careful about our work and what we claim about it.”
In a
comment published with the study, HIV researcher Steven Deeks said the
research provided “the first evidence that ... a cure might one day be
feasible”.
But,
as is common with early clinical trials, the study raised more questions
than answers — including ethical concerns about giving potentially
toxic drugs to HIV-infected people who are otherwise healthy, he said.
“These
data from the lab of David Margolis are genuinely exciting for those
exploring pathways to achieving a cure for AIDS,” Oxford University HIV
researcher John Frater told AFP, calling for investment in further
research.
HIV
immunologist Quentin Sattentau called the findings promising, but said
other types of reservoir cells, including in the brain, may not respond
to this treatment.
“Thus there is a long way to go before we will know if this can work to completely eradicate HIV from an infected person.”
