The positive news served as a stark contrast to the disastrous rollout last year of another drug, marketed as Aduhelm, sponsored by the two companies.
Like Aduhelm, lecanemab reduces abnormal clumps of beta-amyloid, a hallmark of Alzheimer’s. But unlike Aduhelm, where the data were confused and conflicting, the lecanemab trial results told a simple and encouraging story, some experts said. Aduhelm was approved by the Food and Drug Administration, but Medicare refused to cover it broadly, and the drug collapsed on the market.
“A 27 percent reduction in deterioration seems like a modest effect, but for Alzheimer’s patients this could be very meaningful,” said Gil Rabinovici, a neurologist at the University of California at San Francisco.
The trials for Aduhelm were dropped before they were completed, and a post-hoc analysis raised a number of questions. But the lecanemab trial, called Clarity AD, was “completed per protocol” and shows that “lowering amyloid at this stage can translate to a reduction in clinical decline,” Rabinovici said. – It is a major breakthrough.
Some other experts cautioned that the drug’s benefits were likely to be small and said they wanted to see all the data before drawing conclusions.
The companies have already applied to the FDA for accelerated approval for lecanemab, based on data from earlier stages. The FDA’s deadline for a decision is January 6. The companies said the FDA has agreed that the results of the Clarity AD study can serve as a confirmatory study to verify the clinical benefit of lecanemab. That process will continue to move forward.
But Eisai officials said Tuesday that they will also seek full FDA approval for the drug after they receive the expedited approval. Full approval will make it much more likely that the treatment will be covered by Medicare and other insurance companies.
The trial included nearly 1,800 patients with mild cognitive impairment caused by Alzheimer’s or early stage Alzheimer’s.
Eisai, which is taking the lead in developing the drug and working with regulatory authorities, said it will present the full results of the study in late November at an Alzheimer’s conference in San Francisco. The results will also be published in a medical journal, the company said.
Officials said clinical trial participants were tested in several areas to measure the pace of their decline, including memory, orientation and problem solving. Starting at six months, the companies said, the group receiving the treatment fared better than the placebo group. The treatment was administered intravenously twice a month.
The lecanemab group experienced side effects including swelling and bleeding in the brain — complications of anti-amyloid treatments — but the rates were within expectations, the companies said in the release.
Eisai officials also said the results showed that the “amyloid hypothesis” — which claims that removing amyloid plaques can slow the progression of the neurodegenerative disease — is valid. Critics have expressed skepticism about this approach due to several failures involving drugs targeting amyloid.
The trial results “prove the amyloid hypothesis, in which the abnormal accumulation of [beta amyloid] in the brain is one of the main causes of Alzheimer’s disease,” said Haruo Naito, Eisai’s CEO.