Eli Lilly's Alzheimer's drug gets backing from FDA advisers

By Eleanor Laise

Questions remain about how the experimental drug might compete with Biogen and Eisai's Leqembi, analysts say

Eli Lilly & Co.'s experimental Alzheimer's drug donanemab on Monday moved a step closer to U.S. regulatory approval as it won support from an independent panel of advisers to the Food and Drug Administration.

The FDA advisory committee members unanimously voted "yes" on the question of whether the experimental drug has proven an effective treatment for Alzheimer's disease in patients with mild cognitive impairment and mild dementia. In a second vote, committee members unanimously agreed that the benefits of donanemab for that group of patients outweigh its risks.

The FDA does not have to follow advisory committee recommendations, but it often does.

Approval of donanemab would bring a new treatment option to Alzheimer's patients in earlier stages of the disease. Nearly 7 million people in the U.S. are living with Alzheimer's, according to the Alzheimer's Association.

Although donanemab appears likely to win FDA approval, analysts say some big questions remain about how well it might compete with Biogen Inc. and Eisai Co.'s (ESALF) Leqembi, which got full FDA approval last year. Compared with Leqembi, donanemab has been linked with higher rates of potentially severe side effects known as amyloid-related imaging abnormalities, which can involve brain swelling and bleeding.

It may not be possible to achieve the necessary reductions in levels of amyloid, a hallmark of Alzheimer's, without amyloid-related imaging abnormalities, Reisa Sperling, director of the Center for Alzheimer Research and Treatment at Brigham and Women's Hospital, told the FDA's advisory committee Monday. Given the risks, "we haven't hit the full home run," with donanemab and similar treatments, Sperling said. "But right now it is critical to do whatever we can to have an impact" to slow down the progressive disease, she said.

During the open public hearing portion of the meeting, however, some critics of donanemab and similar drugs said the side effects should be taken more seriously. Brain swelling and bleeding are "now hidden behind the benign acronym ARIA," or amyloid-related imaging abnormalities, said Judy Butler, senior research fellow at PharmedOut, a Georgetown University Medical Center research and education project. The term "sounds like a problem with the imaging test," Butler told the advisory committee. But such side effects seen in clinical trials, she said, "should be a flashing neon warning light."

Donanemab's dosing schedule has a potential advantage over that of Leqembi, analysts say, because the once-a-month infusion schedule may be less burdensome for patients, compared with biweekly Leqembi infusions. But Eisai and Biogen have lately taken steps to level the playing field: The companies announced on Sunday that the FDA has accepted Eisai's application for approval of a once-monthly maintenance dose of Leqembi.

In the days leading up to the meeting, the FDA also raised questions about the donanemab clinical-trial design. Lilly's trial allowed patients treated with donanemab to switch to a placebo if their levels of amyloid fell below a certain threshold. The lack of a direct comparison group makes it difficult to assess the merits of stopping treatment for those types of patients, analysts say.

Lilly shares (LLY) gained 1.8% on Monday and are up more than 48% in the year to date. Biogen's stock (BIIB) gained 0.2% Monday and has dropped 12.7% so far this year.

-Eleanor Laise

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06-10-24 1637ET

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