For the first time, a drug has been shown to slow the progression of Alzheimer's disease, offering hope after decades of failed trials. Lecanemab, an antibody that targets amyloid plaques in the brain, reduced cognitive decline by about 27% over 18 months in a trial of 1,795 early-stage patients.
The results, presented at the Clinical Trials on Alzheimer's Disease conference in San Francisco and published in the New England Journal of Medicine, have been described as 'historic' by Professor John Hardy, a leading researcher. Professor Tara Spires-Jones of the University of Edinburgh called the findings 'a big deal' after a long history of 100% failure rates.
However, the effect is modest, with a 0.45-point difference on an 18-point symptom scale. The drug also carries risks, including brain bleeds (17%) and swelling (13%), leading to 7% of participants discontinuing treatment. The impact on daily life is debated, and the drug only works in early stages, requiring better diagnostic methods.
David Essam, 78, from Kent, who took part in the trial, says his Alzheimer's forced him to give up work. His wife Cheryl said the trial gave the family hope. The drug's developers, Eisai and Biogen, plan to seek approval in the US and other countries next year.
Experts caution that longer-term effects are unknown, but the findings mark a turning point. Dr Susan Kohlhaas of Alzheimer's Research UK said it provides a 'foothold' for future drugs. The average time from mild impairment to loss of independence is six years, and slowing decline by a quarter could potentially add 19 months of independent living.
