In the past few years pharmaceutical companies have developed a string of new Alzheimer’s drugs called anti-amyloids, which target amyloid plaques in patients’ brains. These plaques are one of the key biomarkers of the disease.

The first of these drugs, Aduhelm, was approved by the FDA in 2021 amid enormous controversy. The FDA approved the drug despite little evidence that it actually slowed cognitive decline in patients. Biogen, the maker of Aduhelm, pulled the plug on further research or sales of the drug last month.

In January 2023 The FDA approved another anti-amyloid medication from Biogen, lecanemab, sold under the brand name Leqembi. This time, there was much stronger evidence. Clinical trial results showed that the drug showed a modest improvement in cognitive decline in the early phases of the disease. But the drug comes with risks, including brain swelling and bleeding.

Most recently, at the beginning of March, the FDA delayed approval of another anti-amyloid drug, donanemab, created by Eli Lilly. The FDA said it will be conducting an additional review to further scrutinize the study design and efficacy data.

From the outside looking in, these Alzheimer’s drugs appear to be mired in controversy. How well do they actually work? And why has there been so much back and forth with the FDA?

To answer those questions and more, guest host Arielle Duhaime-Ross talks with Dr. Jason Karlawish, professor of medicine, medical ethics and health policy, and neurology at the University of Pennsylvania’s Perelman School of Medicine, and co-director of the Penn Memory Center.

Transcripts for each segment will be available after the show airs on sciencefriday.com.

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