FDA delays Alzheimer’s drug for further review in surprise move

Eli Lilly said Friday that the U.S. Food and Drug Administration is subjecting a proposed Alzheimer’s drug to additional review, a surprise move that will delay regulatory action on a medication that was widely expected to be approved this month.

The FDA will hold an advisory committee meeting to scrutinize the safety and effectiveness of donanemab, a drug designed to attack a sticky substance in the brain known as amyloid beta, which has been linked to the debilitating Alzheimer’s disease that affects some 6 million Americans.

The call for additional scrutiny surprised Lilly executives, who noted that it is unusual for such a review to occur after the FDA has given an anticipated date to make a decision on approval.

“We are confident in donanemab’s potential to offer very meaningful benefits to people with early symptomatic Alzheimer’s disease,” Anne White, an executive vice president at Lilly, said in a statement. The company noted that the FDA held similar reviews for the two amyloid-targeting drugs it has approved, Aduhelm and Leqembi.

The two approved drugs, both made by Cambridge, Mass.-based Biogen and Japan’s Eisai, drew heightened attention because of adverse events such as bleeding in the brain, with particular risk for patients taking blood thinners. Biogen said in January that it would cease marketing Aduhelm, a controversial drug that sputtered commercially after Medicare declined to broadly reimburse for it. The companies are seeking approval for a less-invasive way of administering Leqembi that would make it more convenient for patients.

Clinical trials have shown that donanemab slows cognitive decline of people in the early stages of Alzheimer’s, but the promise of amyloid-targeting drugs remains divisive within the field.

Those drugs don’t reverse the effects of the disease, said Marwan Sabbagh, a behavioral neurologist at the Barrow Neurological Institute who served on the advisory committee for Leqembi.

“The reality is these patients are less worse,” Sabbagh said of amyloid-targeting drugs. “They do not actually get better on these drugs, but we slow the rate of decline.”

Matthew Schrag, a neurologist at Vanderbilt University Medical Center, continues to be skeptical of the focus on amyloid to treat Alzheimer’s. “The absolute magnitude of the benefit is very small,” he said. “We’ve got drugs that are getting a lot of attention that are probably going to leave a lot of patients disappointed.”

Donanemab is administered once a month by an infusion, and only certain medical centers can perform the procedure. Given logistical constraints, Lilly has said that it expects the initial launch of the drug to reach a limited number of patients and only contribute modestly to its earnings once approved.

Lilly’s stock price was down less than 1 percent in premarket trading Friday.

“While the decision is a surprise at this stage in the review process, the safety and appropriate administration of treatments is paramount,” the Alzheimer’s Association said in a statement. “On behalf of everyone who could benefit from this treatment, we strongly urge the FDA to move swiftly in this next stage of its review.”

This is a developing story and will be updated.