In June, the FDA approved the drug aducanumab (Aduhelm) to treat Alzheimer’s disease.

Roughly six million Americans have Alzheimer’s, and drugs typically delay cognitive decline by only a few months, so a new medication is certainly welcome.

As long as it works, that is.

In March 2019, Aduhelm’s prospects weren’t too bright.

A group of independent scientists had examined the data from two nearly identical clinical trials that were then underway. Their conclusion: Aduhelm was so unlikely to slow the early stages of Alzheimer’s that both trials should be stopped. They were.

But seven months later, after Biogen (the drug’s manufacturer) said that it had analyzed additional data, the company claimed that the group receiving a high dose of Aduhelm in one of the trials had actually improved.

Last November, the FDA convened an external expert advisory committee to examine the evidence. In effect, the FDA’s analysis (which was prepared jointly with Biogen!) gave credence to the favorable study’s results and downplayed the unfavorable study’s results.

But the FDA’s own statistician demurred. “The totality of the data does not seem to provide sufficient evidence to support the efficacy of the high dose,” he noted. And, as his presentation showed, even in the favorable study the drug slowed cognitive decline by a mere 0.4 points on an 18-point scale.

The advisory committee voted 10 to 0 (with one “uncertain”) against approving Aduhelm. That should have been game, set, and match, since the FDA doesn’t typically reverse its advisory committees’ decisions.


Instead, the FDA approved the drug, citing evidence that it reduces the amyloid plaques that are often seen in Alzheimer’s...despite the fact that other drugs that reduce amyloid plaques have had no effect on symptoms. Three advisory committee members quit in protest.

The FDA also ordered Biogen to conduct a new trial. Even if it bombs, the company will have had nearly a decade to rake in the profits on a likely ineffective drug that causes small brain bleeds and brain swelling in a substantial fraction of patients. (Aduhelm’s list price: roughly $56,000 a year.)

By one estimate, the FDA’s decision to approve Aduhelm for all Alzheimer’s patients (not just the early-stage patients in Biogen’s studies) would boost Medicare spending on drugs delivered in hospitals and doctors’ offices by 50 percent. That could have raised Medicare premiums and taxes for all. And that’s without the cost of MRI scans to detect the bleeds and swelling.

The Aduhelm story is changing rapidly:

  • OnJuly 8th, the FDA said that only people with early Alzheimer’s should get the drug.
  • A day later, the FDA’s acting commissioner asked for an independent investigation of the agency’s approval process, citing an off-the-books meeting between a Biogen executive and the head of the FDA’s neuroscience division.

My advice: talk to your doctor, but make sure that she or he is familiar with Aduhelm’s disappointing and disturbing backstory.

Peter G. Lurie, MD, MPH
President, Center for Science in the Public Interest