Eisai's Leqembi Receives China Approval, Expanding Alzheimer's Treatment

Eisai Co. Ltd. announced on September 3, 2026, that its subcutaneous formulation of Leqembi (lecanemab) has received approval from the National Medical Products Administration (NMPA) in China for the treatment of early Alzheimer’s disease. This marks the first and only in-home administration option for amyloid-targeting therapy available in the Chinese market.

The approved subcutaneous formulation, known as “レケンビ”オートインジェクター (Leqembi auto-injector), is designed for self-administration, with a dosage of two injections (totaling 500mg) weekly. The approval allows for a transition between intravenous (IV) and subcutaneous (SC) administration, providing greater flexibility for patients and caregivers. Eisai estimates the number of individuals with mild cognitive impairment and mild dementia due to Alzheimer's disease in China at 17 million in 2024, anticipating further increases with the country’s aging population.

The filing details that the approval is based on data from the Clarity AD Phase 3 trial, including subcutaneous administration substudies with a Chinese cohort, demonstrating comparable exposure and expected clinical and biomarker effects to IV administration. Safety profiles for SC administration were generally consistent with those observed in IV administration, with predominantly local injection site reactions. The application received priority review from the NMPA after being submitted in January 2026.

Eisai launched Leqembi in China in June 2024 and anticipates the subcutaneous formulation will be available in the 2026 fiscal year. The company projects a negligible impact on its financial results for the fiscal year ending March 2027 from this approval. The partnership with Biogen will continue, with Eisai leading global development and regulatory submissions, and jointly commercializing and promoting Leqembi. In China, Eisai will handle sales and specialist medical representative activities.

While the approval expands treatment options, the reliance on MRI monitoring for ARIA (Amyloid Related Imaging Abnormalities) remains consistent with the IV administration protocol. The success of the subcutaneous formulation will depend on patient acceptance, adherence to the weekly injection schedule, and the ongoing monitoring for safety signals, as demonstrated in the Clarity AD trial, where the drug showed a 27% reduction in clinical decline over 18 months compared to placebo, measured by CDR-SB.