(Corrects the complete product name in the lead and headline, and its planned launch date in the fourth paragraph)

China's National Medical Products Administration (NMPA) approved Eisai (TYO:4523) and Biogen's subcutaneous autoinjector version of anti-amyloid beta protofibril antibody Leqembi as an initiation treatment for mild cognitive impairment due to Alzheimer's disease or mild AD dementia.

The self-administered autoinjector is given once weekly at 500 mg through two 250 mg injections, according to a joint release on Thursday.

The approval adds at-home subcutaneous treatment to the existing every-two-week intravenous regimen, with patients able to switch between the two administration methods during treatment, the release said.

The product will be launched during Eisai's fiscal 2026, ending March 31, 2027.

Shares of Eisai rose nearly 2% at market close.