Eisai Initiates Formal Application for Subcutaneous Leqembi Alzheimer Disease Treatment

Eisai announced the initiation of the rolling submission of a Biologics License Application (BLA) to the Food and Drug Administration (FDA) for Leqembi (lecanemab-irmb; Eisai, Tokyo, Japan; Biogen, Cambridge, MA) subcutaneous (SC) autoinjector for weekly maintenance dosing to treat individuals with early Alzheimer disease (AD). This announcement follows a recent decision by the FDA to grant Fast Track Designation to the Leqembi SC formulation. In 2023, the FDA approved biweekly intravenous (IV) Leqembi treatment for early stages of AD.

In April, the FDA informed Eisai that the planned BLA rolling submission for SC Leqembi could not be initiated under the Fast Track and Breakthrough Therapy Designations granted to the IV formulation of the medication. Eisai requested a new Fast Track Designation for the SC formulation, which was granted based on positive results from the open-label extension (OLE) study of the phase 3 Clarity AD clinical trial, showing that weekly SC dosing of Leqembi removed 14% more amyloid plaque than biweekly IV treatment. Results from the OLE study were published in TheNew England Journal of Medicine.

Compared with IV formulations, treatment using SC formulations is associated with advantages including greater ease of administration and reduced need for hospital visits and nursing care.

Should the BLA be accepted, Eisai will have permission to introduce Leqembi SC autoinjector into interstate commerce.