2008-07-30 11:33:44
By Emma Wilkinson
Health reporter, BBC News
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Professor Claude Wischik on how the drug has helped patients
UK scientists have developed a drug which may halt the progression of
Alzheimer's disease.
Trials of the drug, known as Rember, in 321 patients showed an 81% difference
in rate of mental decline compared with those not taking the treatment.
The Aberdeen University researchers said the drug targeted the build-up of a
specific protein in the brain.
Alzheimer's experts were optimistic about the results, but said larger trials
were now needed.
Presenting the results at the International Conference on Alzheimer's Disease,
Professor Claude Wischik said the drug may be on the market by 2012.
This bodes well for a Phase III trial, but we need more human trials to assess
the treatment's possible side effects
Rebecca Wood, Alzheimer's Research Trust
Patients with mild to moderate Alzheimer's disease were given either 30, 60 or
100mg of the drug or a placebo.
The 60mg dose produced the most pronounced effect - over 50 weeks there was a
seven-point difference on a scale used to measure severity of dementia.
At 19 months there was no significant decline in mental function in patients
taking the drug, the researchers said.
Imaging data also suggests the drug may be having its biggest effect in the
parts of the brain responsible for memory.
The link between clumps or "tangles" of protein inside nerve cells in the brain
and Alzheimer's disease was first made over 100 years ago.
Later shown to be made up of a protein called Tau, the tangles build up inside
cells involved in memory, destroying them in the process.
SUCCESS STORY
Among the trial patients was Jimmy Hardie, 72. He began taking Rember in March
2006.
His wife said his improvement was gradual, but he is now much more confident.
She said he used to panic when faced with something difficult to do, but now
copes much better.
He keeps busy maintaining old tractors, running a trout fishery, and doing a
lot of gardening.
Mr Hardie said: "It has made a difference to my life. I have my off days - but
I had a lot before."
Rember, or methylthioninium chloride, is the first treatment specifically
designed to target the Tau tangles.
Other treatments for Alzheimer's tend to focus on combating a waste protein in
the brain, beta-amyloid, which is known to form hard plaques. The latest work
suggests targeting Tau may produce better results.
Methylthioninium chloride is more commonly used as a blue dye in laboratory
experiments.
Professor Wischik discovered it by accident 20 years ago, when a drop in a test
tube led to the disappearance of the Tau protein he had been working on.
"We have demonstrated for the first time that it may be possible to arrest the
progression of this disease by targeting the tangles which are highly
correlated with the disease," he said.
"We did an analysis of the effect size at 24 weeks and at 50 weeks compared to
the average effect size of the current treatments and it was about two and a
half times better," he added.
Larger trials of the drug are planned to start in 2009, and researchers are
also investigating whether the drug has a role in prevention of the disease in
the first place.
Professor Clive Ballard, head of research at the Alzheimer's Society, said:
"This is a major new development in the fight against dementia.
"It is the first realistic evidence that a new drug can improve cognition in
people with Alzheimer's by targeting the protein tangles that cause brain cell
death.
"This first modestly sized trial in humans is potentially exciting.
"It suggests the drug could be over twice as effective as any treatment that is
currently available."
Rebecca Wood, chief executive of the Alzheimer's Research Trust, said: "In this
exploratory trial, rember reduced the decline in blood flow to parts of the
brain that are important for memory.
"This bodes well but we need more human trials to assess the treatment's
possible side effects."
She added the fact the trial was funded by a pharmaceutical company highlighted
the lack of funding for Alzheimer's research in the UK.