The US Food and Drug Administration (FDA) has approved the supplemental biologics license application (sBLA) for the intravenous (IV) maintenance dosing of lecanemab-irmb, branded as Leqembi in the US.
The approval, announced by Eisai and Biogen, introduces a once-every-four-weeks maintenance dosing option for patients with early-stage Alzheimer’s disease. This includes individuals with mild cognitive impairment or mild dementia.
Under the new dosing regimen, patients who complete an 18-month initiation phase of bi-weekly dosing at 10 mg/kg may transition to a monthly maintenance schedule of the same dosage. Alternatively, they may continue with the bi-weekly dosing regimen.
The approval aims to improve long-term treatment adherence while maintaining therapeutic outcomes for individuals in the early stages of Alzheimer’s disease.
The sBLA approval is supported by data modelling and simulations based on findings from multiple clinical studies, including the Phase 2 Study 201 and its long-term extension (LTE), as well as the Clarity AD Study 301 and its LTE.
According to Eisai and Biogen, the modelling predicts that transitioning to a four-week dosing schedule after the initiation phase will preserve the clinical and biomarker benefits observed during earlier treatment stages.
Leqembi is already approved for use in several markets, including the US, Japan, China, Israel, South Korea, the UAE, the UK, Mexico, Hong Kong, and Macau.
In November 2024, the treatment received a positive opinion from the European Medicines Agency’s (EMA) Committee for Medicinal Products for Human Use (CHMP), recommending its approval across the European Union. Regulatory submissions are under review in 17 additional countries and regions.
In a related development, the FDA accepted Eisai’s sBLA application in January 2025 for a subcutaneous autoinjector formulation of Leqembi, designed for weekly maintenance dosing. A decision under the Prescription Drug User Fee Act (PDUFA) is expected by 31 August 2025.
Leqembi is the result of a research collaboration between Eisai and BioArctic. The treatment is a humanised immunoglobulin gamma 1 (IgG1) monoclonal antibody targeting aggregated soluble and insoluble forms of amyloid-beta, a protein linked to Alzheimer’s disease pathology.
Eisai leads the global development and regulatory submissions for lecanemab. The Japanese company and Biogen jointly manage commercialisation efforts under a partnership established in 2014.
