A closely watched Alzheimer’s disease medicine looks to be heading toward broader approval, as documents released Wednesday show the Food and Drug Administration appears to have few concerns with it.
The medicine, known scientifically as lecanemab and commercially as Leqembi, was granted a conditional approval earlier this year, based on results from a roughly 850-person study that convinced FDA staff it was reasonably likely to provide some level of benefit to Alzheimer’s patients.
Leqembi’s developers, Eisai and Biogen, have since been trying to secure a full approval. If they succeed, insurance companies are expected to offer much broader coverage of Leqembi and other, similar drugs, which would make them more accessible to patients as well as far more lucrative to their manufacturers.
On Friday, the FDA will convene an external group of advisers to discuss newer data supporting Leqembi and answer a central question: do those results confirm the drug’s benefit to Alzheimer’s patients?
The results in question became available last September and are from a larger study with about 1,800 participants. The study found that, over a treatment period of 18 months, the cognition and function of patients on Leqembi declined 27% slower than those given a placebo. This was determined by a scale widely used to diagnose dementia due to Alzheimer’s, and, according to documents released Wednesday, the FDA views any significant reduction on this scale to be “clinically meaningful.”
In the documents, the agency also detailed safety data from the larger study, as drugs like Leqembi can cause swelling and tiny bleeds in the brains of some patients. These side effects, known collectively as “ARIA,” were seen in 21% of the Leqembi group compared to 9% of the control arm. Most of these cases were mild to moderate in nature and resolved within several months of detection. Biogen and Eisai have said that a small fraction of patients experiencing ARIA showed symptoms.
Three participants in an extension portion of the study, during which all patients were able to receive Leqembi, died. Two of those patients had experienced brain bleeding, while the third had a “possible cerebrovascular accident” and severe ARIA.
The FDA says there’s uncertainty as to what, if any, role Leqembi played in the deaths, although a link to the drug could not be ruled out. The agency has also questioned whether other factors contributed, such as concomitant medications or a condition called “cerebral amyloid angiopathy” that’s common among Alzheimer’s patients.
While FDA staff acknowledge Leqembi’s potential risks, they noted in the briefing documents how safety concerns “can be described in the prescribing information and do not appear to preclude traditional approval of lecanemab."
To Wall Street analysts, these conclusions bode well for Eisai and Biogen. Salim Syed of the investment firm Mizuho Securities noted how the FDA’s briefing documents for Leqembi totaled 35 pages, which is about a quarter of the length of the document issued when the agency sought outside counsel on Aduhelm, Biogen and Eisai’s earlier, more controversial Alzheimer’s drug.
The documents “read super clean — don't really see any surprises here at all,” Syed wrote in a note to clients.
Meanwhile, Brian Abrahams of RBC Capital Markets called the documents “benign” and, in a note to clients, wrote there’s a “high likelihood” Leqembi gets a favorable vote from the FDA’s advisors and, ultimately, a broad label.
Medicare and Medicaid, which cover the vast majority of patients eligible for Alzheimer’s therapies like Leqembi, are expected to expand their current, highly restrictive policies if full approval is granted. With much greater insurance coverage, Abrahams and his team anticipate Leqembi will eventually generate as much as $10 billion in annual sales.