Full approval and Medicare coverage of new Alzheimer’s drug could come in July

The success of Biogen and Eisai’s medicine hinges on the FDA’s decision

Cambridge-based Biogen has a lot riding on the success of Leqembi.Associated Press

A closely watched therapy for Alzheimer’s disease could become more accessible this summer. Cambridge-based Biogen and Japan-based Eisai announced Sunday evening that federal regulators would make a decision whether to grant their drug full approval by July 6, a verdict that all-important Medicare coverage hinges on.

In January, the Food and Drug Administration awarded an accelerated approval to the drug, Leqembi, based on evidence that it removed clumps of sticky proteins known as amyloid in the brains of people in the early stages of Alzheimer’s.

The companies’ previous Alzheimer’s therapy, Aduhelm, won a similar accelerated approval in 2021, but questions about its safety and effectiveness led many hospitals and insurers to restrict access to it, including the Centers for Medicare & Medicaid Services, which covers most of the 6 million people in the United States estimated to live with Alzheimer’s.

Leqembi costs $26,500 a year, not including expensive brain scans and biweekly visits to infusion centers where the drug is administered and where patients are monitored for side effects, putting it out of reach for most patients unless it is covered by insurance.

Medicare officials said in February they probably wouldn’t pay for Leqembi until FDA regulators give it a full approval based on a more thorough review of its ability to actually slow the disease — rather than just remove amyloid proteins linked to the disease. Eisai, which is overseeing interactions with regulators, is confident that Leqembi will meet the bar for full approval.

Last fall, the firm revealed that its drug slowed a common measure of cognitive decline by 27 percent over an 18-month study. The study was heralded as scientifically sound and statistically significant, although doctors disagree on how noticeable that change will be to patients and their families.

Eisai said that the FDA plans to convene a meeting of its advisory committee of independent scientists and doctors to vet the drug, although it hasn’t announced a date.

A similar meeting held for Aduhelm ended disastrously. All but one of the committee members voted against Aduhelm, saying that there was not enough evidence to suggest it slows cognitive decline. When the FDA approved the drug anyway, three high-profile scientists from the committee resigned in protest. Experts believe the new meeting for Leqembi will provide an important opportunity for the companies and the FDA alike to reestablish trust with medical experts and the public — and to differentiate Leqembi from Aduhelm.