TOKYO, Japan / CAMBRIDGE, Massachusetts, USA, July 12, 2026
Eisai Co., Ltd. and Biogen Inc. have announced new clinical and real-world evidence demonstrating that the LEQEMBI® (lecanemab) subcutaneous autoinjector (SC-AI) delivers efficacy and safety comparable to the intravenous (IV) formulation for patients with early Alzheimer’s disease (AD). Presented at the Alzheimer’s Association International Conference (AAIC) 2026 in London, the findings support a more convenient once-weekly, fixed-dose subcutaneous treatment pathway that can be administered at home while maintaining therapeutic performance equivalent to IV infusion. The data reinforce the potential of LEQEMBI SC-AI to improve long-term disease management by providing patients and caregivers with greater treatment flexibility without compromising clinical outcomes. The latest results strengthen Eisai’s leadership in Alzheimer’s disease therapeutics and support the continued expansion of innovative disease-modifying treatment options targeting the underlying pathology of neurodegenerative disease.
Clinical Data Demonstrate Comparable Efficacy and Safety
The clinical presentation highlighted results from the LEQEMBI subcutaneous development program, evaluating pharmacokinetics, pharmacodynamics, efficacy, safety, and patient experience in individuals with early Alzheimer’s disease. The analysis demonstrated that the 500 mg once-weekly subcutaneous autoinjector achieved bioequivalence to the approved 10 mg/kg intravenous regimen administered every two weeks, producing an exposure ratio of 104% while maintaining consistent drug exposure across all body-weight groups. Researchers reported that amyloid plaque removal, clinical efficacy measured by Clinical Dementia Rating–Sum of Boxes (CDR-SB), and the incidence of amyloid-related imaging abnormalities (ARIA-E) were driven by overall drug exposure rather than the route of administration.
The findings support the expectation that subcutaneous LEQEMBI provides clinical efficacy and safety comparable to intravenous therapy, offering patients an effective alternative with the added convenience of at-home administration. Investigators also confirmed that patients could transition flexibly between intravenous and subcutaneous treatment without compromising therapeutic exposure, providing greater flexibility for long-term care.
Real-World Evidence Supports Long-Term Treatment Convenience
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In addition to clinical trial findings, investigators presented real-world evidence from two specialized Alzheimer’s treatment centers in the United States, demonstrating encouraging long-term outcomes among patients receiving subcutaneous LEQEMBI. Patients treated with the subcutaneous formulation experienced slower cognitive decline over 36 months compared with matched natural-history cohorts, while 91% of evaluable patients in a separate case series either remained stable or showed improvement in Mini-Mental State Examination (MMSE) scores during maintenance therapy.
Surveys conducted among patients and caregivers reported high satisfaction rates ranging from 75% to 97%, with convenience ratings between 83% and 97% and willingness to recommend treatment reaching 100% in some groups. The overall safety profile remained consistent with the intravenous formulation, with low immunogenicity, no neutralizing antibodies, and predominantly mild localized injection-site reactions. These results further support the feasibility of expanding treatment beyond infusion centers into home-based care environments.
LEQEMBI Strengthens Long-Term Alzheimer’s Disease Management
The new findings reinforce the importance of early diagnosis and continuous treatment in slowing disease progression among patients with early Alzheimer’s disease. LEQEMBI, a humanized monoclonal antibody targeting soluble and insoluble amyloid-beta aggregates, has already received regulatory approvals in more than 50 countries and regions, with ongoing regulatory expansion for its subcutaneous formulation. Eisai, which leads global development and regulatory activities in collaboration with Biogen, continues advancing both intravenous and subcutaneous treatment strategies to improve patient access and long-term adherence.
By combining disease-modifying efficacy, a well-characterized safety profile, and the convenience of self-administered subcutaneous therapy, LEQEMBI SC-AI represents an important advancement in Alzheimer’s disease care. The results presented at AAIC 2026 further strengthen confidence in subcutaneous administration as a practical and effective option capable of improving treatment accessibility, supporting caregivers, and expanding the future of precision neurology for patients living with early Alzheimer’s disease.
Source: Eisai, Biogen press release
