BioArctic partner Eisai files Japan application for SC Leqembi

Eisai (TYO: 4523) has submitted a new drug application in Japan for a subcutaneous autoinjector version of Leqembi (lecanemab), aiming to give people with early Alzheimer’s disease a once-weekly, at-home option from the start of treatment. If cleared by the Pharmaceuticals and Medical Devices Agency, it would be Japan’s first anti-amyloid therapy available for home injection.

The filing is supported by sub-studies within the Phase III Clarity AD open-label extension showing that a weekly 500mg subcutaneous dose delivered equivalent exposure to the current intravenous regimen, with similar clinical outcomes and less than 2% reporting systemic reactions. Each 250mg injection takes about 15 seconds, and two injections complete the weekly dose.

Eisai says the approach could ease hospital workloads tied to IV infusions, reducing preparation and supervision demands. A comparable submission for initiation dosing has already been sent to the American medicines regulator. In the USA, Leqembi is also approved for subcutaneous maintenance dosing under the brand Leqembi Iqlik.