Some potential Alzheimer’s treatments have resulted in serious side effects that may cause dangerous swelling or bleeding in the brain. Fewer than 10 percent of the patients taking the new drug experienced such effects, the companies reported, making it relatively safe.
The drug works by attacking the stringy amyloid tendrils that form before they begin sticking together into plaques. The results of the trial add evidence to the idea that treatment for Alzheimer’s is most likely to succeed if it starts early in the disease process, because the brain begins to deteriorate years or even decades before full-blown dementia occurs. Some other drugs have failed because they were tried on patients with more advanced Alzheimer’s; others attacked the amyloid at later points in its progression.
Even if study results continue to be positive, making the drug widely available to patients could take years. Dr. Kramer and Ivan Cheung, the chairman and chief executive of Eisai, said that the companies recently submitted a request to meet with the Food and Drug Administration to learn what steps they need to get the drug approved.
“It’s a bit premature to talk about at this point, but our goal is to bring BAN2401 to patients and families as soon as possible,” Mr. Cheung said.
The F.D.A. typically requires Phase 3 clinical trial data to demonstrate safety and effectiveness. However, the agency does have processes for expediting the review of drugs, said a spokeswoman, who declined to comment on this drug or on conditions that would be taken into consideration for an Alzheimer’s drug.
Eisai is the maker of Aricept, one of the only drugs that can help slow early memory decline, but is only effective for about six to nine months. Biogen is the maker of another Alzheimer’s treatment, aducanumab, that has shown early promise in both reducing amyloid and slowing cognitive decline in a small Phase 1 trial. Many in the Alzheimer’s field are intently anticipating the outcome of two large clinical trials of aducanumab, expected to be able to report results in 2020.
Dr. Gandy said the BAN2401 results were encouraging for the prospects of aducanumab because it suggests that there are at least two compounds that may be able to attack both amyloid buildup and cognitive decline.
In early July, when the companies announced they would present positive results from the BAN2401 trial later in the month, the stock prices of both companies rose by about 20 percent and have stayed roughly at that level since.