Biogen and Eisai Strengthen LEQEMBI’s Role in Alzheimer’s Treatment

Eisai Co., Ltd. reported that its anti-amyloid-beta protofibril antibody LEQEMBI® (lecanemab) generated JPY 88.0 billion in global revenue for fiscal year 2025 (April 2025–March 2026), marking the therapy’s first full year of meaningful commercial contribution in Alzheimer’s disease. The United States accounted for the largest share at JPY 44.6 billion, followed by Japan at JPY 24.4 billion and China at JPY 12.4 billion, reflecting stronger early adoption in markets with more established diagnostic pathways and reimbursement systems.

Complementing this annual performance, Biogen Inc.’s first quarter 2026 results show continued commercial momentum. The company reported global in-market sales of $168 million for LEQEMBI, representing a 74% year-over-year increase, including $86 million from the United States, indicating sustained sequential growth and expanding physician uptake. Biogen’s Alzheimer’s collaboration revenue reached $59.5 million, up 80% year-over-year, highlighting the growing financial contribution from the LEQEMBI collaboration.

Taken together, Eisai’s full-year revenue and Biogen’s quarterly performance indicate that LEQEMBI has moved beyond the initial launch phase into a scaling commercial phase. The United States remains the primary growth driver, supported by improving access and clinical adoption, while Japan provides a stable contribution and China continues to develop as an emerging market.

Real-world data further support the therapy’s uptake, with Biogen reporting that approximately 78% of patients remained on LEQEMBI at 18 months, with many continuing into the maintenance phase. This level of persistence suggests sustained treatment continuity, which is important for long-term revenue visibility in a chronic neurodegenerative disease setting.

Eisai leads global development and regulatory activities for lecanemab, while both Eisai and Biogen co-commercialize and co-promote the therapy, combining development leadership with commercial execution across key markets.

Overall, strong annual revenue, continued quarterly growth, and early real-world persistence data position LEQEMBI as a core revenue driver in Alzheimer’s disease therapeutics, while future uptake will remain influenced by factors such as diagnostic capacity, treatment infrastructure, and long-term access across global markets.

Reference

Revenue of LEQEMBI® (Preliminary Basis), April 29, 2026, No.26-24

Biogen reports strong first quarter 2026 results, April 29, 2026, Exhibit 99.1 – Q1 2026 Press Release