Anti-Amyloid Alzheimer's Drugs Show Trivial Cognitive Benefit With Real Brain Bleed Risk
A rigorous Cochrane systematic review pooled 17 randomized controlled trials involving over 20,000 patients to evaluate whether amyloid-beta-targeting monoclonal antibodies — including lecanemab, donanemab, aducanumab, and others — meaningfully slow Alzheimer's progression. At 18 months, cognitive improvements were statistically trivial (SMD −0.11), dementia severity changes were minimal (SMD −0.12), and functional gains were small at best. However, brain swelling (ARIA-E) occurred in 107 more patients per 1,000 treated versus placebo. Serious adverse events and mortality were not increased. The authors conclude that amyloid clearance alone does not translate to clinically meaningful patient benefit, calling for research into alternative disease-modifying mechanisms.