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virus out of hiding risks doing more harm than good: the
treatment itself could be toxic, or it could unwittingly
strengthen the infection.
But over the past few years, leading AIDS researchers
have begun speaking again of the prospects of a cure. For
many, such as Cannon, the goal is a “functional” cure that
would allow patients to stop taking antiretroviral drugs
without risk of harm from the small amount of HIV left
in their bodies. other, more ambitious investigators want
to eradicate the virus totally—what they call a “sterilizing”
cure; they are buoyed by an improved understanding of
what creates and maintains the reservoirs of latent virus.
Either way, the goal is to get HIV-infected people off a
lifetime course of drugs.
Douglas Richman, a virologist at the University of
California, San Diego, who has cared for HIV-infected
people for years, now has patients who have kept the
virus completely in check with drugs for up to 17 years.
“They’re going to outlive me,” says Richman, who is 67
years old. “They’re not going to die of AIDS. That’s won-
derful, but do we have to have tens of millions of people
on lifetime treatment?”
Such treatment has rising costs, both monetary and
medical. In wealthy countries, annual drug expenses run
into the thousands of dollars per HIV-infected person.
Much cheaper generic versions of the drugs have been given to
four million patients in poor countries, but the rich governments
footing most of that bill are now cash-strapped and worried about
sustaining the charity. And an estimated five and a half million
more people urgently need treatment but have no access.
What’s more, living with HIV for decades can be medically
problematic. Even low levels of the virus can leave patients more
susceptible to diseases of aging: heart attacks, malignancies, dis-
orders of the central nervous system. Some of these ailments are
side effects of the drugs themselves. People on treatment can
have damaging surges of virus, too, when they occasionally stop
their drugs or develop resistance to the compounds. “There are
five million new infections a year, and three million deaths,” says
Richman. “So we’re just going to have more and more people liv-
ing with HIV.”
Cannon’s gene therapy experiment is one of a dozen similar
projects in the works that hold the promise of ending patients’
dependence on antiretroviral drugs. It’s an ambitious dream. But
it’s no longer as quixotic as it once seemed, and she is approaching
her experiment with realistic expectations and the conviction that
other researchers’ progress will work in concert with her own. “I
think in steps,” says Cannon. “Will the first person on our treat-
ment be the home run? No. But we may see some benefit. And if
you have an imperfect success, it’s still a success.” Especially when
the goal is so grand that it could profoundly alter millions of indi-
vidual lives—and the course of the AIDS epidemic itself.
Talk of a cure began shortly after the epidemic surfaced in 1981,
but for 15 years it was just talk. Even the best HIV treatments did
little to hamper the virus. Then, in 1996, researchers reported a
remarkable breakthrough using new combinations of antiretrovi-
rals: they could suppress the amount of virus in the blood below the
levels that standard tests could detect, allowing immune systems
to rebound and people near death to resume normal, healthy lives.
Small amounts of the virus could still be detected in these patients
by running more sensitive blood tests and analyzing hideaways
like lymph nodes or the gut, but the dramatic success of the treat-
ment led prominent AIDS researchers to believe for the first time
that the idea of curing HIV was truly realistic.
David Ho, head of the Aaron Diamond AIDS Research Center
in New York City, became a media sensation after he spoke at the
seeking answers In experiments that Cannon and her colleagues
are conducting, human stem cells are transplanted into mice that have
been bred to have no immune systems. Before the transplant, the stem
cells are modified so that a small percentage of the immune cells they give
rise to will be highly resistant to HIV. The hope is that the virus will run out
of immune-cell targets and quickly peter out, effectively curing the animals.
July10 Feature AIDS 46
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