Alzheimer's
Association Cautious About New Alzheimer Treatment Research with
Antibiotics
Chicago,
October 9, 2003
The
Alzheimer's Association expressed caution about new research on two
antibiotics as possible treatments for Alzheimer's disease based on a
study presented today at the Annual Meeting of the Infectious Diseases
Society of
America
(IDSA).
"The data in the study are certainly provocative in
this relatively new area of Alzheimer treatment research," said
William Thies, Ph.D., vice president, Medical and Scientific Affairs for
the Alzheimer's Association.
However, Thies added that the relatively small size of
the study precludes generalization to the larger population of people with
Alzheimer's disease. There is not enough data for the Alzheimer's
Association to recommend antibiotic treatment to physicians, patients and
families.
"The Alzheimer's Association is looking for large,
well-controlled clinical trials before we can make any recommendation one
way or the other about the potential of these two antibiotics as
treatments for Alzheimer's disease," Thies said. "It is just too
early in the process at this point."
Until then, the Alzheimer's Association keeps an open
mind about the possibility that this approach, and others, may someday
prove to be effective in some cases.
"The Alzheimer's Association enthusiastically
supports research for additional and alternative strategies to intervene
with the devastating effects of Alzheimer's disease," said Thies.
"Since its founding in 1980, the Alzheimer's Association has been a
strong advocate for the development of a broad spectrum of interventions
for all stages of the disease."
The Alzheimer's Association, through its scientific
program, has been a champion of drug development using different
approaches and exploiting a variety of different mechanisms of action.
"The eventual goal is to create multiple treatment options so that
physicians can find a therapy that works safely and effectively for every
person with the disease," Thies said.
Newly published research suggests that 4.5 million
Americans now have Alzheimer's disease. As the baby boom generation ages,
the estimated Alzheimer prevalence is 11.3 million to 16 million by 2050.
"The discovery of effective new interventions is urgently needed to
stem the tide of the pending worldwide epidemic of Alzheimer's
disease," Thies said.
Background on the Study
The study, titled "A Randomized Controlled Trial of
Doxycycline and Rifampin for Patients with Alzheimer Disease,"
by Mark Loeb, MD. MSc of McMaster University,
Hamilton
,
Ontario
,
Canada
and colleagues was presented at the 41st annual meeting of the IDSA in
San Diego
.
Researchers studied 101 people with suspected mild to
moderate Alzheimer's disease at five clinics throughout
Canada
. In the study, 50 patients received placebo pills, and 51 were assigned
to take 200 mg of doxycycline and 300 mg of rifampin daily for three
months. The patients, physicians and study investigators were not aware
who was taking which pills.
A well accepted Alzheimer's disease test – the
Standard Alzheimer's Disease Assessment Scale cognitive subscale (SADAScog)
– was given to the patients to determine mental function before the
study began. Six months later, the test was re-administered to 43 people
in the antibiotic group and 39 people in the placebo group – the
remainder had dropped out, died or otherwise did not complete the study.
The scores of those in the antibiotic group declined by an average of 2.75
points less over six months than those who received the placebo (on a
70-point scale). The difference in scores between the two groups was
statistically significant. At 12 months, there was still a difference
between the two groups, although it was not considered statistically
significant.
According to the researchers, adverse effects, including
nausea, diarrhea and sleep disturbances, were relatively minor and there
was no significant difference in their incidence between the two groups.
Previous research, including studies presented at the
8th International Conference on Alzheimer's Disease and Related Disorders
in 2002, suggested that the bacterium Chlamydia pneumoniae may play a role
in causing Alzheimer's disease. The two antibiotics examined in this study
are considered very effective against this germ. However, the study found
no evidence that levels of that bacterium were reduced as significantly as
would be expected. The researchers suggest that the antibiotics may work
by interfering with the accumulation of amyloid plaques around the neurons
in the brain, or the anti-inflammatory effects of these antibiotics may
provide some relief in Alzheimer's.
"More research is needed to uncover the actual
mechanism leading to the results in this study," Thies said.
Plaques made mostly of protein fragments called beta
amyloid are found in the spaces between nerve cells in the brains of
people with Alzheimer's disease. While researchers still do not know what
causes Alzheimer's, it is widely believed that the production of amyloid
plaques is a central feature of the disease. Some laboratory studies have
shown that rifampin may inhibit the buildup of amyloid. Studies in animals
have shown that therapeutic strategies aimed at reducing amyloid
aggregation may be effective in reducing amyloid pathology.
The Alzheimer's
Association
The Alzheimer's Association is the world leader in
Alzheimer research and support. Having awarded more than $150 million to
nearly 1,300 projects, the Association is the largest private funder of
Alzheimer's disease research in the
U.S.
The Alzheimer's Association is working with Congressional leaders to
increase federal funding for Alzheimer research from the estimated $640
million the National Institutes of Health will spend in 2003 to $1 billion
annually.
The Alzheimer's Association's vision is a world without
Alzheimer's disease. For more information about Alzheimer's disease, visit
www.alz.org or call 800-272-3900.
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