Eli Lilly Alzheimer's treatment solanezumab failed to slow disease progression

Eli Lilly on Wednesday said it will halt development of its Alzheimer's treatment candidate solanezumab after the antibody failed to slow disease progression.

Solanezumab's failure is a blow to efforts to treat Alzheimer's in people who are in the very early stage of the disease and have not yet shown clinical symptoms.

The study enrolled more than 1,000 seniors who had normal memory and thinking function, but showed signs of brain plaque that is associated with Alzheimer's.

Solanezumab did not clear or halt accumulation of the plaque, called amyloid, and did not slow cognitive decline in the participants who received the treatment.

"These data suggest that we may need to be more aggressive with amyloid removal even at this very early stage of disease," said Dr. Reisa Sperling, a neurologist at Brigham and Women's Hospital and the director of the study.

Solanezumab was designed to target plaque that floats in the brain. Lilly is developing two other Alzheimer's treatments that are in late-stage clinical trials, donanemab and remternetug. These antibodies target plaque that has deposited on the brain and are designed to treat people who have early symptoms of the disease.

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Lilly is expecting to publish clinical trial data on donanemab in the second quarter of this year. The company plans to ask the Food and Drug Administration to approve the treatment if that data is positive.

Lilly had asked the FDA for expedited approval of donanemab but the agency rejected the company's request in January. The agency told Lilly that it needs to submit data on at least 100 patients who received the treatment for 12 months.

Lilly said it did not have that data because donanemab cleared brain plaque quickly in many patients.

"Due to the speed of plaque reduction that we saw, many patients were able to stop dosing as early as six months into treatment, resulting in fewer patients receiving 12 months or more of donanemab dosing," Dr. Dan Skovronsky, Lilly's chief scientific officer, told analysts during the company's earnings call in February.

"We remain confident in the of potential donanemab as a new treatment for people with early symptomatic Alzheimer's disease," Skovronsky said.

The FDA approved Eisai's and Biogen's early Alzheimer's treatment Leqembi on an expedited basis in January. The companies expect the agency to make a decision on full approval in July.

Medicare will only cover Alzheimer's antibody drugs that receive expedited approval for people participating in clinical trials. The public health insurance program for seniors said it will provide broader coverage as soon as the FDA grants full approval.