Lecanemab
LeqembiUniProt P05067 · 3D model
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A lab-made antibody that clears sticky amyloid-beta clumps from the brain, the buildup thought to drive Alzheimer's disease.
How it works
Alzheimer's disease is marked by sticky clumps of a protein called amyloid-beta building up in the brain. Lecanemab is an antibody engineered to grab onto these clumps — especially the smaller, soluble ones thought to be more toxic to brain cells — and flag them for clearance, which measurably shrinks plaque buildup on brain scans. Patients who cleared more amyloid this way tended to show slower cognitive decline in trials, though the exact chain of cause and effect between clearing the plaques and protecting thinking ability isn't fully mapped out yet.
What it’s used for
Used to treat Alzheimer's disease, specifically meant to be started early — in patients with mild memory or thinking problems, or mild dementia, not more advanced stages, since that's the group it was actually tested in.
- Mechanism
- Amyloid-beta protofibril-directed antibody (mAb)
- Drug class
- Monoclonal antibody
- Therapeutic area
- Neurology
The first Alzheimer's drug proven, not just hoped, to slow the disease
For about twenty years, drug after drug aimed at Alzheimer's disease failed to actually slow it down in a real, confirmed way, even when they cleared the sticky amyloid plaques the disease is known for. Lecanemab was the first to break that streak: in a large trial, patients taking it experienced measurably slower decline in memory and daily function than patients on placebo, not just less plaque on a brain scan. That's why the FDA gave it full, traditional approval rather than the narrower, evidence-still-pending approval an earlier amyloid drug had received — it's the first Alzheimer's treatment the FDA has confirmed actually does what patients and families hope it will.
Pivotal trial
An 18-month, randomized, placebo-controlled phase 3 trial in early Alzheimer's disease, in which lecanemab slowed decline on the primary cognitive/functional endpoint (CDR-SB) by about 27% relative to placebo.