Eisai Approves Subcutaneous Leqembi for Alzheimer's Treatment in Japan
News related to:BioArctic AB · 2 min read
STOCKHOLM, Sept. 16, 2026 /CourierPR/ -- BioArctic AB's partner Eisai has announced that the subcutaneous autoinjector formulation of Leqembi, known as Leqembi Pen in Japan, has been approved for use in Japan. This approval marks a significant advancement in the treatment of early Alzheimer's disease, offering patients an alternative to the existing intravenous (IV) formulation.
Leqembi Pen allows patients or their care partners to self-administer treatment, with two injections (totaling 500 mg) given once weekly. This new route of administration is expected to reduce the burden of clinic visits and streamline the overall Alzheimer's disease treatment pathway. According to Eisai, each injection takes approximately 15 seconds, making it a more convenient option for patients.
The approval in Japan is the third globally for the subcutaneous formulation of Leqembi. The decision is based on the integrated results of data and associated modeling and simulation from the 18-month core study of the Phase 3 Clarity AD study of Leqembi in patients with mild cognitive impairment (MCI) due to Alzheimer's disease (AD) or mild AD dementia. Additional subcutaneous administration sub-studies in the subsequent long-term extension (LTE) also contributed to the approval.
Leqembi Pen is designed to be administered at home, with the option to self-administer after a physician's initial supervision. The company notes that the overall safety profile of subcutaneous administration is generally similar to that of IV administration, with systemic injection/infusion-related reactions observed less frequently (1.4%) compared to IV administration.
BioArctic AB has been collaborating with Eisai since 2005, focusing on the development and commercialization of drugs for neurodegenerative diseases. Leqembi, the world's first drug proven to slow the progression of Alzheimer's disease, is currently approved in 53 countries and under regulatory review in six countries and regions. The IV formulation of Leqembi is approved for use in nine countries, including the United States, Japan, China, and the United Kingdom.
The subcutaneous formulation of Leqembi Pen is expected to lower barriers to initiating and continuing treatment, potentially reducing the time required for administration compared to IV infusions. This could help reduce the overall burden on healthcare resources associated with IV administration, such as nurse monitoring and maintaining infusion capacity.
The approval in Japan is part of a broader strategy by Eisai to expand the accessibility of Leqembi to more patients. The company is also conducting ongoing clinical studies, including the AHEAD 3-45 trial, which aims to evaluate the efficacy of Leqembi in individuals with preclinical Alzheimer's disease.
In summary, the approval of the subcutaneous formulation of Leqembi Pen in Japan represents a significant milestone in the treatment of early Alzheimer's disease, offering patients a more convenient and accessible option.