The causes of Alzheimer’s disease are not fully understood, but leading scientists believe that it is due to a molecule called beta-amyloid forming plaque in the brain. Beta-amyloid is assumed to interfere with the normal functioning of nerve cells, leading to their degeneration and eventually memory problems and loss of cognitive ability in the patient.
In two major clinical studies, scientists have now shown that certain antibodies – bapineuzumab and solanezumab – may reduce the harmful effects of beta-amyloid.
Professor Kaj Blennow at the Sahlgrenska Academy, a world-leading Alzheimer’s researcher, and co-author in one of the studies explain that treatment with bapineuzumab seem to reduces the accumulation of beta-amyloid in the brain, and probably also reduces the degeneration of nerve cells. However, no positive effects on disease symptoms were noted in the patients, probably because the treatment was initiated relatively late in the course of the disease.
Slows the cognitive decline
When the researchers in a parallel study tested solanezumab in a group of individuals with mild Alzheimer’s, they found that the antibody could slow the cognitive decline.
‘Both antibodies seem to have an effect, but in different ways. Somewhat simplified, bapineuzumab directly attacks the harmful molecule in the brain, whereas solanezumab binds soluble beta-amyloid and aggregates thereof in the brain tissue
The results, published in New England Journal of Medicine, are from so-called phase 3 clinical studies, which is one of the final steps in the development of new medicines.
One problem is that the scientists only relied on clinical assessments and memory testing to diagnose Alzheimer’s. Since memory tests are very unspecific, many individuals without Alzheimer’s may have been included in the studies, which may have substantially affected the possibility of finding a positive effect of the substances.
The articles Two Phase 3 Trials of Bapineuzumab in Mild-to-Moderate Alzheimer’s Disease and Phase 3 Trials of Solanezumab for Mild-to-Moderate Alzheimer’s Disease were published in NEJM on 23 January.
Kaj Blennow, professor at the Sahlgrenska Academy, University of Gothenburg
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