Alzheimer Drugs Targeting Beta-Amyloid
We do not know what causes Alzheimer's disease. Many scientists believe that one of the main causes has to do with beta-amyloid. It is called the 'amyloid hypothesis'. Beta-amyloid is a tiny microscopic protein present in the brain. They believe that the destruction of brain cells seen in Alzheimer's disease is caused by faults in the way beta-amyloid is produced, how it accumulates and how it is got rid of.
Scientists are exploring and developing drugs that may block or inhibit the production of beta-amyloid. Some research has reached human clinical trials. Animal studies in mice have suggested that anti-beta-amyloid drugs can reduce brain amyloid levels and improve memory problems in diseases similar to Alzheimer’s disease. There is no clear evidence at the present time that these drugs can improve Alzheimer symptoms or protect brain cells.
Beta-amyloid and the Alzheimer's Brain Explained
Beta-amyloid is a small piece of a larger protein called a amyloid precursor protein. Scientists believe that Beta-amyloid is produced under certain circumstances when the amyloid precursor protein (APP) extending through the brain cells is cut by other proteins into smaller sections.
Beta-amyloid is said to be stickier than the other sections produced when the amyloid precursor protein (APP) is cut. It is these accumulations of beta-amyloid that form amyloid plaques that are considered to be one of the main signs of Alzheimer's disease.
More information about plaques and tangles
Drugs Under Development That Inhibit or Block Beta-amyloid
Scientists are looking at the way that proteins called secretases cut the APP (amyloid precursor protein) so that they can stop or reduce or change beta-amyloid production in the brain.
One of the examples of drugs currently undergoing human trials hoping to change the way secretase works is Flurizan (R-flurbiprofen) produced by Myriad Pharmaceuticals.
Another type of drug under trial aimed at blocking beta-amyloid are called anti-aggregants. A Phase III clinical trial of an anti-aggregant, NC-758 Alzhemed began in August 2004. Blocking beta-amyloid is complex as it is not known which form of beta amyloid is the most toxic to the brain or if drugs should be developed to stop the beta-amyloid sticking together to prevent plaque formation.
Vaccine Type Drugs Under Development for Alzheimer's Disease
There are two main strands to this type of drug development.
A recent experimental vaccine that underwent human trials to mobilize their own antibodies had to be stopped as some of them developed serious brain inflammation. Although the trial had to be stopped there were a number of positive signs and observable results that indicate the vaccine, known as AN-1792, may be a future hope and treatment for Alzheimer's disease. Brains of some trial participants who died of unrelated illness showed fewer plaques than were anticipated. Those with fewer plaques appeared overall to show slower rates of decline. On the negative side some participants showed greater brain shrinkage and overall vaccine trial participants showed no improvement against the placebo group in memory, thinking and in their overall function.
Scientist are continuing to investigate this type of vaccine. More information about vaccine trial that was stopped
Laboratory produced antibodies to beta-amyloid may provide another treatment for Alzheimer's. Rather than getting the person's own body to produce the antibodies a laboratory produced alternative may be more effective. The antibodies could be given in specific dosage and when the drug is stopped the antibodies would no longer present. There are a number of drug companies developing engineered anti-beta-amyloid antibodies. One of them is Elan.
Hope for the Future. Alzheimer's Disease Anti-Beta-Amyloid Drug Development
Alzheimer's is a devastating disease that affects millions of people world wide. Pharmaceutical companies are keen to exploit this potentially huge market so it gives us all hope that in the future a cure, a preventive vaccine or a treatment will be discovered that will rid us of Alzheimer's disease.
Article Sources: Alzheimer's Society, CDC, World Health Organization, Dr.Roger Rosenberg Archives of Neurology, Dec 13, 2004, Elan Corporation and Wyeth Pharmaceuticals.
