Newswise — A study led by Mayo Clinic shows for
the first time that a drug appears to have a
slowing effect -- though limited -- on the
progression from mild cognitive impairment
to Alzheimer’s disease. The findings will be
published online in the New England
Journal of Medicine on April 14.
“Our findings represent an important shift in the
field of Alzheimer’s disease treatment, in
that this is the only study to date to
demonstrate the ability to push back the
clinical diagnosis of the disease,” says
Ronald Petersen, M.D., Ph.D., Mayo Clinic
neurologist and lead investigator of the
trial.
“This may be the sign of new horizons to
come in attempting to alter the Alzheimer’s
disease process as early as possible, buying
time for those who may later progress.”
Dr. Petersen and his co-investigators are
optimistic about these findings and what
they represent. Rather than focusing on the
effects of the particular drugs tested, Dr.
Petersen indicates he is enthusiastic about
the underlying concept -- causing any amount
of postponement in the heretofore
unstoppable progression of Alzheimer’s
disease.
“This study may be the front-runner in
shifting our sights toward earlier treatment
of the Alzheimer’s process, laying the
groundwork for testing other drugs,” says
Dr. Petersen.
“Mild cognitive impairment patients are a
great population of people to target,
hopefully with other treatments as well.”
This randomized, double-blind,
placebo-controlled, multicenter study
compared vitamin E; donepezil, an
Alzheimer’s treatment drug; and placebo for
delay or prevention of progression to
Alzheimer’s disease in mild cognitive
impairment patients. These patients had the
amnesic (memory-related) variety of mild
cognitive impairment, a transitional stage
between the forgetfulness of normal aging
and the more serious memory decline and
other problems associated with Alzheimer's
disease.
Over the first year of the three-year trial,
mild cognitive impairment patients treated
with donepezil had a reduced risk of
progressing to Alzheimer’s disease compared
to patients who took placebo, an inactive
pill. Although the patients treated with
donepezil initially progressed to
Alzheimer’s disease at a slower rate than
patients treated with vitamin E or placebo,
the risk of progression to Alzheimer’s
disease was the same among all three
treatment groups by the end of the study.
Vitamin E had no effect on slowing the
progression to Alzheimer’s disease over the
course of the study.
The study found one subset of patients for whom
the effect of the donepezil treatment lasted
longer, up to two to three years: those
possessing a particular genotype called
Apolipoprotein E4.
Previous studies have shown those with
Apolipoprotein E4 genotype have a higher
propensity to develop Alzheimer’s than the
general population.
The investigators are not recommending
genotyping, or administering tests to
determine genetic makeup of patients with
mild cognitive impairment. In addition,
while they are not recommending treatment
with donepezil for all mild cognitive
impairment patients, Dr. Petersen indicates
that the findings of this study open the
door for discussion of donepezil treatment
on an individual basis for patients with
mild cognitive impairment.
For example, donepezil might be considered
as an option for mild cognitive impairment
patients who want an aggressive approach, he
explains.
This study involved 769 participants at 69
medical centers in the United States and
Canada. The National Institute on Aging
funded this study with additional support
from Pfizer, Eisai and DSM Nutritional
Products.
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