Eisai Submits New Marketing Application for Leqembi® with Extended Dosing Schedule

Eisai, a prominent partner of BioArctic AB, has recently announced a significant development in the treatment of early Alzheimer's disease. On January 26, 2026, the company submitted a proposed Marketing Authorisation Variation to the European Medicines Agency (EMA) for lecanemab, marketed under the brand name Leqembi®. The proposed change aims to adapt the current intravenous (IV) dosing schedule, allowing for maintenance doses every four weeks instead of the previously established biweekly regimen.

Lecanemab is currently approved by the European Union for patients diagnosed with mild cognitive impairment (MCI) or mild dementia due to Alzheimer's disease. The treatment is particularly aimed at patients who are non-carriers of the apolipoprotein E ε4 (ApoE ε4) gene variant, a known genetic risk factor for the disease, who also have confirmed amyloid pathology. Under the new proposal, patients would initially receive lecanemab through an IV infusion every two weeks for a duration of 18 months. After this initial period, the treatment regimen would transition to once every four weeks, enhancing the convenience for patients.

This development marks a critical step in Eisai's ongoing efforts to optimize the treatment experience for patients with early Alzheimer's disease. Eisai emphasizes that treatment should be discontinued if the patient progresses to moderate Alzheimer's disease, thus ensuring a tailored approach to individual patient needs and disease progression.

The relationship between BioArctic and Eisai has proven to be pivotal in the progression of lecanemab. The antibody, which tackles aggregated and soluble forms of amyloid-beta (Aβ), emerged from a robust collaboration, initially leveraging the groundbreaking research of Professor Lars Lannfelt who discovered the Arctic mutation in Alzheimer's disease.

Eisai carries the responsibility for clinical development, regulatory applications, and the commercialization of lecanemab globally. BioArctic maintains commercialization rights in the Nordic regions, preparing to launch alongside Eisai. With lecanemab now approved in 53 countries and under review in seven more, this new application represents a worldwide push towards improving therapeutic protocols for Alzheimer's disease.

A noteworthy aspect of lecanemab’s journey involves its application in various clinical trials and studies. The ongoing Phase 3 clinical study, known as AHEAD 3-45, focuses on individuals with preclinical Alzheimer's disease. This long-term study, a collaboration among Eisai, Biogen, and the Alzheimer's Clinical Trial Consortium, highlights the partnership's commitment to advancing Alzheimer's research. Since its completion of recruitment in October 2024, the study aims to provide new insights into the efficacy of lecanemab in preventing the onset of more serious symptoms in early-stage patients.

Further expanding its research horizons, Eisai is involved in the Tau NexGen clinical study, which examines Dominantly Inherited Alzheimer’s Disease (DIAD) and incorporates lecanemab as the core anti-amyloid therapy. Such studies underline the extensive groundwork Eisai and BioArctic have laid in the realm of Alzheimer's treatment, indicating a strong backing for improving patient outcomes.

Moreover, lecanemab's remarkable application has prompted regulatory advancements in multiple territories. Notably, it has been included in the