Lecanemab for Alzheimer’s disease

The detailed results of a phase 3 randomised controlled trial of lecanemab,1 the latest monoclonal antibody drug for Alzheimer’s disease, prompted feverish media coverage heralding a new era of disease modifying treatments. Such treatment has been long hoped for, for differing reasons, by patients, clinicians, researchers, governments, and drug companies. However, the null effects on cognition of other anti-amyloid agents,23 the tiny effect on cognition reported for lecanemab, and concerns about safety4 mean that perspective is needed. Hyperbolic rhetoric gives patients and their families false hope, which clinicians must address, and pre-empts regulatory decision making.

Unlike previous trials of anti-amyloid immunotherapy, the lecanemab trial found a statistically significant result, indicating that the reported difference between placebo and treatment groups in average rate of cognitive decline was unlikely to be due to chance. The prevailing narrative is that this trial “succeeded” where others have “failed.” In reality, lecanemab, like other anti-amyloid agents, successfully cleared amyloid from the brain. This clearance had no discernible effect on cognition …