Biogen Idec and Eisai have joined forces to co-develop and co-commercialise drug candidates that address multiple mechanisms in Alzheimer’s disease (AD), beginning with two clinical-stage drugs from Eisai’s pipeline: the BACE (β-site amyloid precursor protein cleaving enzyme) inhibitor E2609; and BAN2401, an anti-amyloid beta (Aβ) monoclonal antibody. As part of the deal, Eisai also has an option to develop and commercialise jointly two of Biogen’s AD drug candidates, the Phase Ib Aβ antibody BIIB037 and an unspecified anti-tau monoclonal antibody. Currently, only symptomatic therapies are available for AD.