Marilynn
Marchione Associated Press
It may
be too late to stop Alzheimer's in people who already have some mental decline.
But what if a treatment could target the very earliest brain changes while
memory and thinking skills are still intact, in hope of preventing the disease?
Two big studies are going all out to try.
Clinics
throughout the United States and some other countries are signing up
participants — the only studies of this type enrolling healthy
older people.
"The
excitement in the Alzheimer's field right now is prevention," said Dr.
Eric Reiman, executive director of the Banner Alzheimer's Institute in Phoenix,
which is leading the work.
Science
so far has failed to find a drug that can alter the progression of Alzheimer's,
the most common form of dementia; 146 attempts have failed over the last
decade, a recent industry report found. Even drugs that help remove the sticky
plaques that clog the brains of people with the disease have not yet proved
able to stave off mental decline.
It may
be that they were tried too late, like lowering cholesterol after someone has
suffered a heart attack whose damage can't be undone, Reiman said.
"What
we have been learning, painfully, is that if we really want to come up with
therapies that will modify the disease, we need to start very, very, very
early," said Dr. Eliezer Masliah, neuroscience chief at the National
Institute on Aging.
His
agency is funding the prevention studies with the Alzheimer's Association,
several foundations, and Novartis and Amgen, makers of two experimental drugs
being tested.
The
goal is to try to block the earliest steps of plaque formation in healthy
people who show no symptoms of dementia but are at higher risk for it because
of age and a gene that makes it more likely.
To
participate, people must first join GeneMatch, a
confidential registry of folks interested in volunteering for various
Alzheimer's studies who are ages 55 to 75 and have not been diagnosed with any
mental decline.
They
are checked for the APOE4 gene, which doesn't destine someone to develop
Alzheimer's but raises that risk. About one in four people have one copy of the
gene and about 2 percent have two copies, one from each parent.
More
than 70,000 people have signed up since the registry began three years ago,
said Jessica Langbaum, one of the Banner study leaders.
"Most
of them have been touched by the disease personally," either by having a
family member or close friend with it, she said.
Langbaum's
67-year-old mother, Ivy Segal, gave a DNA sample through a cheek swab and
joined the registry in August. Her father was a patient at Banner and died of
Alzheimer's in 2011 at age 87. Watching him go from a mild-mannered man whose
smile could light up a room to what he was like when he died was devastating,
she said.
Being
in GeneMatch doesn't necessarily mean you'll find out if you have the gene —
folks with and without it may be contacted about various studies. But to be in
one of the two prevention studies, people must agree to learn their APOE4
status and have at least one copy of the gene.
Participants
get periodic brain scans and memory and thinking tests every six months. They
are given experimental drugs or placebo versions of them for several years.
One
study is enrolling people with two copies of the gene. They are given either
shots every few months of a drug intended
to help the immune system clear plaque from the brain or daily pills of a drug intended
to prevent first steps of plaque formation, or placebo versions of these
experimental treatments.
The
other study is in people who either have two copies of APOE4 or one copy of the
gene plus evidence on brain scans of plaque starting to build. They will get
one of two doses of the drug to prevent plaque formation or placebo pills.
Larry
Rebenack, 71, of the Phoenix suburb of Surprise, Arizona, joined GeneMatch in
August.
"I
have a lot of friends and acquaintances I've seen deteriorate," including
one who started blowing through stop signs on a route to a golf course they had
safely traveled for years, and another who forgot not only where he had parked
his car but even what kind of car it was," Rebenack said. "It's a
disease that takes a little part of you away each day."
Rebenack
has decided to learn whether he has the gene if researchers give him the chance
to find out.
"It's
like any other piece of information. It helps you plan your life and you owe it
to all your loved ones, too."
Marilynn
Marchione can be followed at @MMarchioneAP .
The
Associated Press Health & Science Department receives support from
the Howard Hughes Medical Institute's Department of Science Education. The AP
is solely responsible for all content.
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