BioArctic AB partner Eisai announced that the subcutaneous autoinjector formulation of Leqembi (known as Leqembi Pen in Japan) has been approved as a new route of administration for the treatment of early Alzheimer's disease.

Leqembi Pen enables patients or care partners to self-administer treatment, with two injections (totaling 500 mg) given once weekly. This approval in Japan provides people living with early Alzheimer's disease with an additional treatment option, allowing once-weekly subcutaneous administration at home, complementing the existing intravenous (IV) formulation, which is administered every two weeks in a hospital setting.

Leqembi Pen may reduce the time required for treatment administration compared with IV infusions, with each injection taking approximately 15 seconds. The option for at-home administration may reduce the burden of clinic visits for patients and their care partners and provide a treatment option that better fits their lifestyles. 

The subcutaneous treatment option is expected to lower barriers to initiating and continuing treatment and has the potential to reduce healthcare resources associated with IV administration, such as nurse monitoring and maintaining infusion capacity. This may help streamline the overall Alzheimer's disease treatment pathway.

As with IV administration, monitoring for ARIA (amyloid-related imaging abnormalities) involves brain magnetic resonance imaging (MRI) before treatment is initiated and at specified time points thereafter.

Japan is the third country globally to approve the subcutaneous formulation of Leqembi. This approval is based on the integrated results of data and associated modeling and simulation from the 18-month core study of the Phase 3 Clarity AD study of Leqembi in patients with mild cognitive impairment (MCI) due to AD or mild AD dementia (collectively referred to as early AD), as well as multiple subcutaneous administration sub-studies in its subsequent long-term extension (LTE). Once-weekly administration of the 500 mg subcutaneous formulation demonstrated similar exposure to IV administration once every two weeks and supported the expectation that the subcutaneous formulation provides efficacy comparable to that of the IV formulation. The overall safety profile of subcutaneous administration was generally similar to that of IV administration, while systemic injection/infusion-related reactions were observed less frequently with subcutaneous administration (1.4 per cent) compared with IV administration.