Eisai has signed an agreement for the divestiture of rights for Merislon and Myonal, two of its long-standing products in Japan, to Kaken Pharmaceutical.

The transaction is valued at Y3.8bn ($25.10m).

Merislon treats vertigo and equilibrium disturbances and Myonal is a muscle relaxant, which patients have used since their respective launches in 1969 and 1983.

The agreement stipulates that Eisai will complete the transfer of marketing capabilities by March 2025, followed by manufacturing and marketing approval transfer.

The deal will not impact Eisai's consolidated financial forecast for 31 March 2024.

The company stated: “Eisai has determined that divesting rights for these products to Kaken, which has strengths in the products’ disease areas, is the optimal choice to ensure they continue contributing to a greater number of patients.”

Eisai will continue to focus on creating and delivering products to target diseases with higher unmet medical needs such as neurology, oncology and global health.

Kaken is a research and development-driven pharmaceutical company that focuses on orthopaedics and dermatology.

Earlier this month, Eisai received approval for the amyloid beta-directed antibody Leqembi (lecanemab-irmb) in China to treat mild cognitive impairment associated with Alzheimer’s disease (AD) and mild AD dementia.

Leqembi, developed in partnership with BioArctic, will be available in the region in the third quarter of 2024. The approval in China is based on the international Phase III Clarity AD study.

Eisai will be responsible for distribution and information provision through expert medical representatives.