Overview

• France’s Haute Autorité de Santé on Sept. 9 refused early access to Leqembi, citing modest efficacy and a worrying safety profile that includes potentially fatal brain hemorrhages and edema.
• The European Medicines Agency in 2025 backed restricted use for mildly affected patients with safeguards, including genetic screening for higher risk of brain edema or bleeding.
• Monoclonal antibodies Leqembi (lécanémab) and Kisunla (donanémab) are the first in decades to slow early decline, yet benefits remain limited to early-stage patients and come with serious safety risks.
• A first blood-based biomarker test won U.S. authorization in May, while the U.K. has launched a clinical trial to assess real-world impact; most European systems have not authorized such tests.
• Prevention research identifies many risk factors, but randomized programs show little to modest cognitive benefit, with a recent JAMA study reporting only small slowing over two years.