Eli Lilly’s Alzheimer’s Drug Gains Unanimous FDA Panel Backing

A Food and Drug Administration (FDA) advisory panel on Monday unanimously voted to endorse donanemab, Eli Lilly’s monoclonal antibody drug for early-stage Alzheimer’s disease.

In 2023, around 6.7 million Americans had Alzheimer’s disease, according to one estimate. This number is projected to double to 13.9 million people by 2060. There is currently no cure for the disease.

Like Leqembi—an FDA-approved drug for Alzheimer’s made by Eisai and Biogen—Lilly’s donanemab may slow the progression of Alzheimer’s symptoms. Aduhelm, also made by Biogen, was approved in 2021 but discontinued due to concerns over its efficacy, side effects, and high cost.

These three drugs all work in the same way: by removing amyloid plaque deposits from the brain, which may be one cause of Alzheimer’s disease.

Safety and Efficacy of Donanemab

The clinical trial to support donanemab’s application for approval included 1,736 patients between 60 and 85 years of age. Researchers found that donanemab slowed the progression of Alzheimer’s by 29% over 18 months, compared to a placebo.

The FDA advisory committee agreed that donanemab is effective at treating Alzheimer’s patients at the early stages of the disease and that the benefits of the drug outweigh its risks.

During the trial, three patients taking donanemab died after developing brain bleeding and swelling known as amyloid-related imaging abnormalities (ARIA). Several cases of ARIA occurred with both Aduhelm and Leqembi as well, which is why regular brain imaging is required for the drugs.

To reduce ARIA risks, Eli Lilly said it plans to ask patients to get a brain scan after the first infusion since most patients who had the condition did so in the first few weeks of the clinical trial.

If donanemab is approved, it will be “important to minimize the risk of ARIA with careful monitoring and to have detailed discussions with patients and care partners regarding individual risk-benefit and allow patients and their care partners to make informed decisions for themselves and their loved ones,” said Reisa Sperling, MD, a professor of neurology at Harvard Medical School, an outside expert who was invited to speak to the advisory committee.

The FDA panelists noted that almost all of the trial participants were White, which means there’s not much information on the effectiveness of the drug in other populations.

Who Might Be Eligible for Donanemab?

Patients seeking Aduhelm or Leqembi had to go through brain imaging or a spinal tap to prove they had amyloid beta buildups in their brains. Lilly also scanned participants in the donanemab trial for tau, another protein linked to Alzheimer’s disease.

In the trial, patients with low-to-medium levels of tau in their brains, in addition to amyloid, showed slower clinical decline than patients who only had amyloid.

However, Lilly didn’t recommend requiring tau scanning for the drug. Most of the FDA advisers agreed, saying brain imaging for tau could increase the cost of testing and delay eligible people’s access to the drug. The FDA will decide whether testing for tau will be required for donanemab.

Lilly also required patients to stop taking donanemab if their amyloid levels dropped below a certain level. The committee was concerned about the need for more follow-up testing and whether patients whose amyloid returned would again be eligible for the drug.

How Is Donanemab Administered?

Donanemab, like Leqembi and Aduhelm, is given as an infusion at a clinic or hospital, which could be a barrier for some patients. Leqembi is given every two weeks, while donanemab is given monthly.

Eisai and Biogen have recently submitted an application to the FDA for an autoinjector version of Leqembi to be used as a maintenance treatment following a certain number of infusions. Neuroimmune, the original developer of Aduhelm, also reacquired the rights to the drug from Eisai and Biogen last year and is also working on an injectable version of Aduhelm.

What Do Health Experts Think of the Drug?

While donanemab is not a cure for Alzheimer’s disease, patient advocacy organizations and health experts welcome this drug as a pathway to developing better treatments.

“If approved, donanemab will expand the first class of disease-modifying drugs, serving as the building blocks for future generations of drugs,” Howard Fillit, MDcofounder and chief science officer of the Alzheimer’s Drug Discovery Foundation, said in a statement. “Anti-amyloids are not a silver bullet, but they offer opportunities for patients to modify the course of the disease while the field works towards developing more novel therapies that target the underlying biology.”

In a statementthe Alzheimer’s Association also expressed enthusiasm about the potential FDA approval of donanemab. The organization said it “strongly encourages prescribers to participate in the Alzheimer’s Network for Treatment and Diagnostics (ALZ-NET), which is gathering real-world data on how people from all backgrounds and communities respond to novel FDA-approved Alzheimer’s therapies.”

Cathryn Ann Devons, MD, a geriatric medicine specialist at Phelps Hospital in Sleepy Hollow, NY, told Verywell that she praises the decision to recommend approval. “This can give hope to patients suffering from Alzheimer’s and their families to have something new on the horizon to try.”