Scientists from Cambridge University have raised doubts about the efficacy and long-term benefits of two new Alzheimer's drugs, lecanemab and donanemab. Despite recent market introductions, the researchers highlight significant concerns regarding side effects, small proven benefits, and challenges in drug administration. The two drugs target amyloid plaques in the brain, believed by some to be a cause of Alzheimer's. While trials show these drugs can slow disease progression, the absolute effect sizes are deemed small and clinically insignificant.
Lecanemab, developed by Eisai and Biogen, and donanemab, by Eli Lilly, showed modest success in late-stage trials. Donanemab slowed cognitive decline by 22% to 29%, and lecanemab by a minor difference on a cognition scale. However, side effects such as brain edema and hemorrhage were significant, with up to 36.8% of donanemab users affected. The long-term effects beyond the 18-month trials remain unknown, raising concerns about the drugs' overall impact and safety.
These new treatments have divided regulatory opinions. The FDA approved lecanemab and donanemab, while the European Medicines Agency opposed lecanemab's license, citing the risk of side effects over benefits. The UK’s MHRA is still assessing lecanemab. Implementing these treatments involves substantial resources and frequent hospital visits, which could be challenging, especially in low- and middle-income countries. The study underscores the need for balanced patient information and alternative strategies for improving dementia care.
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