TOKYO and CAMBRIDGE, Mass. — February 9, 2026 — Leads & Copy — Eisai Co., Ltd. and Biogen Inc. announced that the Biologics License Application (BLA) for the subcutaneous formulation (SC-AI) of LEQEMBI® (lecanemab) has been designated for Priority Review by China’s National Medical Products Administration (NMPA).
The application, accepted in January 2026, is for an anti-amyloid beta (Aβ) protofibril antibody.
The NMPA’s Priority Review and Approval Procedure aims to accelerate the launch of new medicines with significant clinical value by shortening the assessment period.
If approved, the SC-AI of 500 mg (two 250 mg injections) could allow for once-weekly at-home administration from the start of treatment, offering an alternative to the current IV administration every two weeks in a hospital. Each 250 mg injection takes approximately 15 seconds.
Eisai estimates that in 2024, there were 17 million patients in China with MCI or mild dementia due to AD, and the number is expected to rise with the aging population.
LEQEMBI was launched in China in June 2024 and is available in the private market. It has also been included in the “Commercial Insurance Innovative Drug List,” effective January 2026, under new government policies supporting innovative medicines.
Based on this list, commercial insurance companies will develop insurance products covering LEQEMBI.
Eisai leads LEQEMBI’s development and regulatory submissions globally, with Eisai and Biogen co-commercializing and co-promoting the product; Eisai has final decision-making authority. In China, Eisai will distribute the product and provide information through specialized Medical Representatives.
The potential approval of SC-AI would provide patients and care partners with the option of receiving LEQEMBI treatment at home. The SC formulation also has the potential to reduce healthcare resource use for IV dosing, such as infusion preparation and nurse monitoring, while streamlining the AD treatment care pathway.
Notes to Editors:
1. About LEQEMBI (generic name: lecanemab, Chinese brand name: 乐意保)
Lecanemab, developed through a strategic research alliance between Eisai and BioArctic, is a humanized immunoglobulin gamma (IgG1) monoclonal antibody targeting aggregated soluble (protofibril) and insoluble forms of amyloid-beta (Aβ). It is approved in 53 countries and regions, including Japan, the United States, China, Europe, South Korea, Taiwan, and Saudi Arabia, and is under regulatory review in 6 countries. Following initial treatment every two weeks for 18 months, intravenous (IV) maintenance dosing every four weeks has been approved in 7 countries, including the U.S., China, the UK, and applications have been filed in 7 countries and regions. The U.S. FDA approved Eisai’s Biologics License Application (BLA) for subcutaneous maintenance dosing with LEQEMBI IQLIK in August 2025. A Supplemental Biologics License Application (sBLA) for initiation treatment was accepted in January 2026 and has been granted Priority Review, with a Prescription Drug User Fee Act (PDUFA) action date of May 24, 2026. In November 2025, an application for a subcutaneous injectable formulation was submitted in Japan. In January 2026, the Biologics License Application (BLA) for the subcutaneous formulation was accepted in China. In December 2025, Lecanemab (IV) was included in the “Commercial Insurance Innovative Drug List” introduced by the National Healthcare Security Administration (NHSA) of China.
Since July 2020, the Phase 3 clinical study (AHEAD 3-45) for individuals with preclinical AD is ongoing. Since January 2022, the Tau NexGen clinical study for Dominantly Inherited AD (DIAD) is ongoing and includes lecanemab as the backbone anti-amyloid therapy.
2. About Protofibril
Protofibrils are believed to contribute to the brain injury that occurs with AD and are considered to be the most toxic form of soluble Aβ, having a primary role in the cognitive decline associated with this progressive, debilitating condition. Protofibrils cause injury to neurons in the brain, which in turn, can negatively impact cognitive function via multiple mechanisms, not only increasing the development of insoluble Aβ plaques but also increasing direct damage to brain cell membranes and the connections that transmit signals between nerve cells or nerve cells and other cells. It is believed the reduction of protofibrils may prevent the progression of AD by reducing damage to neurons in the brain and cognitive dysfunction.
3. About the Collaboration between Eisai and Biogen for AD
Eisai and Biogen have been collaborating on AD treatments since 2014. Eisai leads lecanemab development and regulatory submissions, with both companies co-commercializing and co-promoting the product; Eisai has final decision-making authority.
4. About the Collaboration between Eisai and BioArctic for AD
Since 2005, Eisai and BioArctic have had a collaboration regarding the development and commercialization of AD treatments. Eisai obtained global rights to study, develop, manufacture, and market lecanemab for AD treatment per an agreement with BioArctic in December 2007. The development and commercialization agreement on the antibody lecanemab back-up was signed in May 2015.
5. About Eisai Co., Ltd.
Eisai’s Corporate Concept is “to give first thought to patients and people in the daily living domain, and to increase the benefits that health care provides.” Under this Concept (also known as human health care (hhc) Concept), we aim to effectively achieve social good in the form of relieving anxiety over health and reducing health disparities. With a global network of R&D facilities, manufacturing sites and marketing subsidiaries, we strive to create and deliver innovative products to target diseases with high unmet medical needs, with a particular focus in our strategic areas of Neurology and Oncology.
6. About Biogen
Founded in 1978, Biogen is a biotechnology company that pioneers science to deliver new medicines to transform lives and create value. They apply deep understanding of human biology and leverage different modalities to advance treatments or therapies that deliver superior outcomes.
Biogen Safe Harbor
This news release contains forward-looking statements regarding the potential clinical effects of lecanemab (marketed as 乐意保 in China); the potential benefits, safety and efficacy of lecanemab; potential regulatory discussions, submissions and approvals and the timing thereof including for LEQEMBI (lecanemab) subcutaneous autoinjector (SC-AI); the potential to expand options and reduce healthcare resources by treating Alzheimer’s disease at home; the anticipated benefits and potential of Biogen’s collaboration arrangements with Eisai; the potential of Biogen’s commercial business and pipeline programs, including lecanemab; and risks and uncertainties associated with drug development and commercialization.
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References
Amin L, Harris DA. Aβ receptors specifically recognize molecular features displayed by fibril ends and neurotoxic oligomers. Nat Commun. 2021;12:3451. doi:10.1038/s41467-021-23507-z
Ono K, Tsuji M. Protofibrils of Amyloid-β are Important Targets of a Disease-Modifying Approach for Alzheimer’s Disease. Int J Mol Sci. 2020;21(3):952. doi: 10.3390/ijms21030952. PMID: 32023927; PMCID: PMC7037706.
Source: Eisai Co., Ltd.
