Biogen & Partner Eisai Get EU Nod for Alzheimer's Drug Leqembi

Biogen BIIB and partner Eisai announced that the European Commission (EC) has granted marketing authorization to Leqembi (lecanemab) for early Alzheimer’s disease (AD).

The regulatory body has approved Leqembi as a treatment for adult patients with early AD who are apolipoprotein E ε4 (ApoE ε4) non-carriers or heterozygotes with confirmed amyloid pathology in Europe.

Biogen’s partner, Japan-based Eisai, leads the clinical development and regulatory submissions for Leqembi. Though both companies co-commercialize and co-promote the drug, Eisai has the final decision-making authority.

Year to date, shares of Biogen have plunged 23.5% compared with the industry’s decline of 6.5%.

EU Nod for BIIB & Eisai's Leqembi Comes After Initial Delay

The approval for Leqembi in the EU is a positive for Biogen and Eisai, as it comes after several hurdles that delayed the approval timeline of the drug.

The European Medicines Agency’s (EMA) Committee for Medicinal Products for Human Use (CHMP) had given a negative opinion regarding the marketing approval of Leqembi for early AD in July 2024.

Although patients given Leqembi had lower CDR-SB scores than those given placebo, the difference between the two groups was small. Hence, the CHMP believed that the observed effect of Leqembi on delaying cognitive decline does not counterbalance the risk of serious adverse events associated with the drug.

The most important safety concern with Leqembi was the frequent occurrence of amyloid-related imaging abnormalities (ARIA), leading to swelling and potential bleeding in the brain. Back then, the CHMP was concerned by the fact that the risk of ARIA is more pronounced in people who have a certain form of the gene for the protein apolipoprotein E called ApoE4. Eisai requested the CHMP to re-visit its opinion.

Eventually, in November, the CHMP rendered a positive opinion recommending the marketing approval for Leqembi (lecanemab) for early Alzheimer’s disease for patients who are ApoE4 non-carriers or heterozygotes with confirmed amyloid pathology in Europe.

In January 2025, the EC had requested the CHMP to reassess new safety data that emerged after the positive opinion and determine if any updates were needed. After reviewing the additional data, the CHMP, in February, concluded that its positive opinion for Leqembi does not need to be updated and reaffirmed its positive opinion by consensus.

BIIB, Eisai's Leqembi Approved in Other Countries

Leqembi gained full approval from the FDA for early AD in the United States s in July 2023. The drug is also approved in China, Japan, Great Britain and several other countries.

Though Leqembi’s launch was slow, sales picked up in 2024, showing sequential improvement. The positive trend is expected to continue in 2025. Eisai recorded nearly $87 million in global revenues from Leqembi sales in the fourth quarter of 2024, showing a solid sequential improvement of 30%.

A less frequent maintenance intravenous dosing version of Leqembi was approved by the FDA in January 2025, while a regulatory application for the subcutaneous autoinjector is under review with a decision from the FDA expected on Aug. 31, 2025.

Eisai and Biogen believe that Leqembi has the potential to generate blockbuster sales, as there is a huge unmet medical need for AD treatments.

Other Players in the AD Space

Currently, there are two FDA-approved drugs in the AD space — Leqembi and Eli Lilly’s LLY Kisunla. The FDA approved Kisunla last year.

Both Biogen/Eisai’s Leqembi and Lilly’s Kisunla are approved to treat early symptomatic AD, which includes mild cognitive impairment or the dementia stage of the disease.

The Biogen/Eisai and Lilly drugs are based on similar mechanisms, reducing the accumulation of amyloid beta (Aβ) plaque in the brain. Aβ is a protein that is said to be the primary cause of the cognitive decline associated with AD.

Small biotech Prothena Corporation PRTA is also developing several candidates in early-stage studies targeting the AD indication.

PRTA is evaluating PRX012, also an amyloid-targeting therapy, in an early-stage study. Prothena is also developing a dual Aβ-tau vaccine, PRX123, a potential prevention and treatment for AD.

PRTA expects to report multiple clinical data readouts later in 2025.

BIIB's Zacks Rank

Biogen currently has a Zacks Rank #3 (Hold). You can see the complete list of today’s Zacks #1 Rank (Strong Buy) stocks here.

Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report

This article originally published on Zacks Investment Research (zacks.com).

Zacks Investment Research