By John Schieszer, Medical Tribune News Service.
VANCOUVER, CANADA -- Canadian researchers say a new class of
drugs recently approved to treat the pain and inflammation of
arthritis, called COX-2 inhibitors, may have a role in preventing
and treating Alzheimer's disease (AD).
``What you are after in dealing with Alzheimer's disease is to
reduce the inflammation in the brain,'' said Dr. Patrick McGeer of
Kinsmen Laboratory of Neurological Research at the University of
British Columbia. ``One hopes these will work because treatments
for Alzheimer's disease are desperately needed and there is very
strong data that the nonsteroidal anti-inflammatory drugs (drugs
such as ibuprofen used to treat arthritis) will work in this
disease. It is just people are afraid of the gastrointestinal side
effects.''
Two COX-2 inhibitors have recently been approved by the Food and
Drug Administration. These drugs, celecoxib (Celebrex) and
rofecoxib (Vioxx) now both are being tested in clinical trials with
AD patients.
Speaking at the Ninth International Congress of the
International Psychogeriatric Association (IPA) in here on Aug. 17,
McGeer presented data on what role COX-2 inhibitors may have in the
treatment of AD.
``To date there is no approved treatment that will delay the
death of neurons so at the present time people with Alzheimer's
disease are condemned to a loss of neurons as though there were no
treatment at all,'' said McGeer. ``The NSAIDs offer promise of
delaying or perhaps even preventing neuronal death. That is why it
is so urgent that this type of treatment be evaluated.''
COX-2 inhibitors work by inhibiting the enzyme COX-2 without
significantly inhibiting COX-1. COX-1 produces prostaglandins that
are believed to be responsible for maintaining normal body
functions, including the protection of the lining of the stomach.
COX-2 is responsible for producing prostaglandins that are believed
to be primarily responsible for pain and inflammation. NSAIDs
inhibit both COX-1 and COX-2, which can result in more stomach
upset.
``COX-2 inhibitors appear promising because they may slow down
some of the inflammatory response that mediates the damage in
Alzheimer's disease,'' said Preston Mason, who is an associate
professor of biochemistry and medicine at MCP Hahnemann School of
Medicine in Pittsburgh.
But despite these theories of how COX-2 inhibitors may help in
AD, some AD researchers say they may be less effective than NSAIDs.
While COX-2 inhibitors result in fewer serious gastrointestinal
side effects than traditional NSAIDs, making them good candidates
for long-term therapy, they also may be too specific in their
action.
``The short answer is we just don't know,'' said Dr. John
Morris, who is a professor of neurology at Washington University
School of Medicine in St. Louis. ``The first study may report
results in the next six to 12 months. Frankly, I don't think we
will have the full story.'' He added: ``The COX-2 inhibitors are
very attractive because of their side effect profile, but we don't
[yet] know the COX-2 enzyme distribution in the brain.''
