A great deal about Alzheimer’s Disease remains a mystery, but one well-documented aspect of the condition is that the brain shrinks as dementia worsens. Indeed, brain shrinkage is one of the hallmarks of the disease, and the greater the shrinkage (or atrophy), the worse the dementia.
That’s why some researchers are concerned by the finding that the recently approved Alzheimer’s drugs, Leqembi and Kisunla, speed up brain atrophy rather than slow it.
Advocates for the drugs say that brain atrophy shows the drugs are working, because they reduce inflammation in the brain and remove amyloid, a protein associated with Alzheimer’s. According to this theory, brain tissue volume shrinks as amyloid is destroyed and swelling goes down.
But skeptics argue the amount of amyloid removed could only account for about one one-thousandth of the volume loss observed in patients. They worry that the drugs are destroying healthy brain tissue and causing atrophy. This concern was reinforced when the U.S. Food and Drug Administration (FDA) noted in June of last year that a protein called neurofilament light, which builds up when brain cells die, increases in patients taking one of the new drugs.
