STOCKHOLM — November 13, 2026 -- Eisai has launched Leqembi Pen, a once-weekly subcutaneous form of lecanemab for early Alzheimer's disease, in Japan. The launch comes 58 days after the September 16, 2026 approval, BioArctic said. Japan is the second country after the US where the subcutaneous formulation is on sale.
Leqembi Pen enters Japan's NHI price list as a 500 mg weekly dose
The product is now on Japan's National Health Insurance (NHI) Drug Price List. The approved dose is 500 mg once a week, given through two autoinjector pens. By FairsOnline's calculation, that is 52 doses and 104 pens a year. The intravenous (IV) option, given every two weeks in a medical facility, works out to 26 infusion visits a year at that interval. The release did not disclose the NHI price.
Eisai says the pen is the only at-home anti-amyloid option in Japan
Eisai describes Leqembi Pen as the first and only anti-amyloid treatment in Japan that allows at-home administration. After training, patients can inject themselves. A family member or care partner can also give the dose under a physician's guidance.
The company says home use may reduce clinic visits and healthcare resource use compared with IV treatment. It gave no figures. Clinic contact does not disappear: as with IV dosing, MRI monitoring for amyloid-related imaging abnormalities (ARIA) is required before treatment starts and at specified points afterwards.
BioArctic collects royalties on global Leqembi sales without development costs
Under its agreements with Eisai, BioArctic carries no development costs for lecanemab in Alzheimer's disease. It is entitled to sales milestone payments and royalties on global sales, so Japanese sales of the pen fall within that royalty base. Eisai is responsible for clinical development, market applications and commercialization. BioArctic holds the right to co-commercialize in the Nordic region.
Subcutaneous dosing is now approved in three markets named in the release: the US, China and Japan. Leqembi overall is approved in 53 countries, with six more reviews under way. Subcutaneous initiation treatment was approved in China and Japan in September 2026, and applications are under review in four countries.