A New Old Cure for Alzheimer's
A classic drug against schistosomiasis, which has been known for 30 years and has around 300 million sufferers worldwide, is intended to further improve the treatment options for Alzheimer's disease. Ten days ago, the German pharmaceutical company Bayer applied for European registration of the substance metrifonate for the treatment of this form of dementia. In 1999, the approval for metrifonate should take place. The drug is characterized by a long duration of action and very good tolerability.
The application for registration was announced at an international press seminar organized by the German group on the subject of Alzheimer's dementia in Paris. Initial data from studies on patients were also presented. Just a few weeks ago at the European Alzheimer's Congress in Helsinki, even neurologists had only been presented with results from animal experiments.
Behind these research efforts is an unprecedented challenge for society and he althcare in the coming decades. The world is facing an avalanche of Alzheimer's disease.
Univ.-Prof. dr Albert Hofman from the Institute for Epidemiology and Biostatistics at the Erasmus University in Rotterdam (Netherlands): There are practically no demented people among the 65-year-olds. At the age of 70, the proportion of those affected is two percent, among the 75-year-old it is already eight percent - and among the 95-year-old finally 50 percent.
Two thirds of all cases of these brain disorders are caused by Alzheimer's disease. There are currently around 2.5 million Alzheimer's patients in the EU; in 2010 there will be four million. The head of the symposium, Univ.-Prof. dr Orgogozo (Bordeaux/France): Alzheimer's disease is deadly, common and expensive.
To blame for this is the demographic development. In western industrialized countries, the number of people over 75 is growing the fastest of all age groups. The states on the border to industrial society (South America, Asia) are catching up fast. Hofman: A study in the EU found that the annual risk of a 90-year-old developing Alzheimer's disease is ten percent.
In the event of a full outbreak of the disease, the care of the confused patients who no longer recognize themselves and their loved ones must be ensured around the clock. And that at an age when even the existing partner is slightly overwhelmed and the social networks of the old extended family no longer exist.
Edward Truschke, President of the American Alzheimer's Association: Four million people are already affected in the United States. Your care is a 36-hour job. The disease currently costs us $100 billion a year in the United States. By 2050, 14 million Alzheimer's patients are expected in the United States.
A cure for Alzheimer's disease is currently not in sight. The Heidelberg expert Univ.-Prof. dr Konrad Beyreuther: The disease is a breakdown in the transport of the so-called amyloid precursor protein (APP) in nerve cells of the brain. The protein itself has a repair and signaling function. If it is not broken down properly, it is deposited in the brain and the function of the nerve cells collapses - similar to a traffic jam.
The first symptoms noticed by the affected person's relatives – severe forgetfulness, confusion, changes in behavior – are probably preceded by a 30-year subclinical process. But when the disease broke out, considerable damage had already been done to the brain. This also results in the chances of early intervention. The US Alzheimer's expert Edward Truschke: If you could delay the onset of the disease for five years, there would be 50 percent fewer patients.
This is exactly what the first drugs against Alzheimer's disease aim to ensure. These are known as acetylcholinesterase inhibitors. In the gaps between nerve cells in the brain, they block the enzyme that breaks down the stimulating messenger substance acetylcholine. Tacrine was the first such substance, but it has potentially strong side effects, making treatment difficult. Two other medicinal products have already been approved in Europe or are about to be registered. Metrifonat is to come in 1999.
The clinical tests with the new substance (dosage: 30 to 60 milligrams once a day) have been successful. Bayer representative Perry de Jongh, who coordinates the studies on patients worldwide: We have experience with therapy for up to six months.
Compared to a placebo, the new substance produced results that are typical for acetylcholinesterase inhibitors: an improvement in brain performance by one "point" on the internationally used ADAS-cog scale (Alzheimer's Disease Assessment Scale). The patients remained stable for the first three months, over a period of six months. In contrast, the condition of the placebo subjects steadily deteriorated.
At the same time, according to previous experience, metrifonate is characterized by a linear dose-response relationship (predictable effect), simple dosage and a long duration of action. Furthermore, the side effects – diarrhea, leg cramps and runny nose – are only slightly pronounced.
What is most important: The treatment has to start as early as possible, so as not to intervene when the Alzheimer's patient's brain is already severely damaged. Work is underway on simple laboratory tests to specifically diagnose the disease. The British expert Univ.-Prof. dr Ian Hindmarch, who even developed Bayer's own test suitable for general practitioners (Activity of Daily Living Score – ADL): We simply have to diagnose Alzheimer's disease earlier.
Otherwise, there is currently no way to get a grip on the disastrous consequences of the disease. – Without optimal medical care, patients fall prey to deadly oblivion.
