Leqembi for Alzheimer Disease Launches in First European Union Countries

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Eisai and Biogen today announced that the anti-amyloid beta (Aβ) monoclonal antibody lecanemab-irmb (Leqembi) for the treatment of Alzheimer disease (AD) has been launched in Austria on August 25, 2025, and will be launched in Germany on September 1, 2025.¹ Leqembi received approval from the European Commission (EC) in April 2025 as the first therapy that targets an underlying cause of AD.² Germany and Austria will mark the first launches in the EU.

Leqembi is indicated for the treatment of adult patients with a clinical diagnosis of mild cognitive impairment and mild dementia due to AD (also known as early AD) who are ApoE ε4 noncarriers or heterozygotes with confirmed amyloid pathology.

In the wake of the EC approval, Eisai has collaborated with the regional and local health care authorities to coordinate the mandatory authorization requirements ahead of Leqembi’s launch. The required controlled access program is now in place in Austria and Germany, which has enabled the launch in these first 2 EU countries.

With a lack of new treatment options that slow the progression of AD, there is a significant unmet need. Leqembi fights AD in 2 ways: targeting amyloid plaque and protofibrils, which can impact tau downstream. In the 18-month, multicenter, double-blind, phase 3 Clarity AD clinical trial, the primary endpoint was the global cognitive and functional scale, Clinical Dementia Rating – Sum of Boxes (CDR-SB). In the EU indicated population of ApoE ε4 noncarriers or heterozygotes, measured by controlled-based multiple imputation, treatment with lecanemab (n=757) reduced clinical decline on CDR-SB by 31% at 18 months compared with placebo (n=764). The most common adverse reactions were infusion-related reaction (26%), ARIA-H (13%), headache (11%) and ARIA-E (9%). Symptomatic ARIA-E occurred in 2% of participants. Symptomatic ARIA-H occurred in 0.8% of patients.³

While Eisai serves as the lead for lecanemab’s development and regulatory submissions globally and has final decision-making authority, both Eisai and Biogen cocommercialize and copromote the product together. In the EU, excluding the Nordic countries, Eisai and Biogen will copromote the medicine and Eisai will distribute the product as the Marketing Authorization Holder.

Leqembi’s launch in the US was a road marked with challenges: It received breakthrough therapy designation back in July 2021 and full FDA approval in July 2023, but struggled to achieve market success, despite its overall better reception than aducanumab.^4,5 In May 2024, Eisai and Biogen initiated a rolling submission for subcutaneous Leqembi, as the fast track designation did not extend to the new subcutaneous formulation. The rolling submission, originally scheduled for March of 2024, was delayed after the FDA requested additional 3-month immunogenicity data on the subcutaneous formulation proposed maintenance dose of 360 mg weekly.^6,7 Despite these setbacks, the FDA accepted a Biologics License Application for Leqembi subcutaneous autoinjector for weekly maintenance dosing in January 2025, with a Prescription Drug User Fee Act action date set for August 31, 2025.⁸

References

1. Austria and Germany to become the first markets in the European Union (EU) to launch LEQEMBI® (lecanemab). News release. August 25, 2025. Accessed August 25, 2025. https://www.eisai.com/news/2025/pdf/enews202557pdf.pdf

2. Leqembi® (lecanemab) is the First Medicine that Slows Progression of Early Alzheimer’s Disease to be Authorized in the European Union. News release. April 16, 2025. Accessed August 25, 2025. https://www.eisai.com/news/2025/pdf/enews202532pdf.pdf

3. van Dyck CH, Swanson CJ, Aisen P, et al. Lecanemab in early Alzheimer’s disease. N Engl J Med. 2023;388:9-21.

4. Kuntz L. Biogen discontinues aducanumab for Alzheimer disease. Psychiatric Times. January 31, 2024. https://www.psychiatrictimes.com/view/biogen-discontinues-aducanumab-for-alzheimer-disease

5. Kuntz L. Moving forward: Alzheimer treatment granted breakthrough therapy designation. Psychiatric Times. July 30, 2021. https://www.psychiatrictimes.com/view/moving-forward-alzheimer-treatment-granted-breakthrough-therapy-designation

6. Kuntz L. Rolling submission for subcutaneous lecanemab. Psychiatric Times. May 15, 2024. https://www.psychiatrictimes.com/view/rolling-submission-for-subcutaneous-lecanemab

7. O’Brien E. FDA: specific fast track designation for subcutaneous formulation of Leqembi for Alzheimer disease needed for rolling review. Psychiatric Times. April 3, 2024. https://www.psychiatrictimes.com/view/fda-specific-fast-track-designation-for-subcutaneous-formulation-of-leqembi-for-alzheimer-disease-needed-for-rolling-review

8. Kuntz L. FDA accepts Biologics License Application for lecanemab-irmb. Psychiatric Times. January 14, 2025. https://www.psychiatrictimes.com/view/fda-accepts-biologics-license-application-for-lecanemab-irmb