It is easy to be doubtful about announcements of drugs that claim to slow the progress of Alzheimers, the most common form of dementia (痴呆). A new drug called Lecanemab, however, may be the real deal. Results of a clinical trial, conducted by its makers, Eisai, of Tokyo, and Biogen, of Cambridge Massachusetts, have just been announced in the New England Journal of Medicine(November; 2022). After18 months, it had slowed the progress of symptoms by a quarter.
The trial involved 1795 participants who were in the early stages of the illness. Half received the drug. The others, a placebo(安慰剂). It showed two things. One was the modest but measurable slowing of progression. The other was that an explanation of Alzheimers called the Amyloid Hypothesis(淀粉样蛋白假说) seems correct.
Amyloid is a protein which accumulates in parts of the brains of those with Alzheimers, which is an established sign of the illness. Lecanemab, containing a special antibody, is found to be able to attach itself to amyloid and then attracts immune-system cells to clear the protein away (and measurably did so in those receiving the drug).That suggests amyloid does indeed directly create problems associated with dementia and that Lecanemab can slow down the development of the disease.
This is a small first step. Some experts question whether the test used to show an improvement in symptoms is clinically meaningful because amyloid can be detected only with the help of a piece of expensive equipment, which is not something that can easily be turned into a routine program. Moreover, Lecanemab also caused swelling and bleeding of the brain in a number of participants. Now that the new drug has been shown to work, it can be followed up with further tests. Hope for more good news soon.
