What We Know About Lecanemab, the New Alzheimer’s Drug

Updated: Jan. 11, 2023

The medicine offers hope for patients who have struggled to find effective treatments.

Good news came last week in the form of FDA approval of a new Alzheimer’s drug called lecanemab that’s been shown to slow down the disease’s progression in clinical trials. While it’s not a cure, this new drug offers some hope to patients. Read on to learn more.

What Is the Newest Drug for Alzheimer’s?

The new drug, lecanemab, will be sold under the brand name Leqembi. It’s a monoclonal infusion that can be administered every two weeks to patients in earlier stages of the disease.

According to a phase 3 clinical trial of 1,795 patients, organized by the developing companies Eisai and Biogen in September 2022, lecanemab slowed cognitive decline by 27 % after 18 months of usage. Lecanemab works by removing beta-amyloid plaques, the hallmark pathology of Alzheimer’s, from the brain.

When Was Lecanemab Approved—and For Who?

Lecanemab was approved by the FDA on Friday, Jan. 6, 2023, through the FDA’s accelerated program. These unique approvals are reserved for medicines that “fill an unmet medical need.” The drug is intended for use in patients with mild cognitive impairment or mild dementia stage of the disease.

Accelerated approvals do not, however, award drug-developing companies carte blanche; additional clinical trials are required to confirm the drug’s benefits. If benefits cannot be proven, the drug will be removed from the market.

The approval of lecanemab was based on a mid-stage trial of the drug among 856 Alzheimer’s patients. The FDA did not seek guidance from its advisory board and has yet to review the results of the aforementioned phase 3 trial. Representatives claimed in an interview with NBC that they would do so “soon.”

What Is the Cost of Lecanemab?

The drug’s cost is expected to ring in at around $25,000 annually for one patient, according to Ivan Cheung, the U.S. Chairman and CEO of Eisai. Insurers are still deciding whether to cover it and for whom. The Centers for Medicare and Medicaid Services, for instance, currently limit the coverage of amyloid-targeting drugs. These insurance decisions will likely result in a few months’ wait time for any interested patients.

What Else to Know About Lecanemab


Neurologists are currently debating the effectiveness of lecanemab. In an article from the Herald Standard , journalist Matthew Perrone cited Washington University neurologist Dr. Joy Snider as saying that this drug could result in “an extra six months to a year of someone being able to drive.”

On the other hand, in the same article, Dr. Matthew Schrag, a neurology researcher at Vanderbilt University claimed, “Most patients won’t notice the difference[…] This is really quite a small effect and probably below the threshold of what we’d call clinically significant.”

Associated Risks

The drug is not without its potential side effects. In the same 2022 phase 3 trial, 17% of those who received the drug experienced brain bleeding, compared to 9% of placebo users. Additionally, 12.6% of users reported brain swelling, compared to 1.7% in the placebo group. At least three deaths due to hemorrhage may be linked to the usage of lecanemab.

Cheung says the company is nonetheless “confident” in its drug. Cheung cited the “emotional turmoil” and “devastati[on]” of families with someone suffering from Alzheimer’s, believing the benefits to outweigh the potential costs.