Eisai seeks expanded Japanese indication for Aricept

Japanese drug major Eisai (TYO: 4523) says it has filed an application for its already marketed anti-Alzheimer's drug Aricept (donepezil hydrochloride) in Japan, requesting a new indication expansion to use the agent in the treatment of dementia with Lewy bodies (DLB).

DLB is considered to be one of Japan's three major types of dementia, alongside Alzheimer's disease and vascular dementia. In addition to progressive cognitive impairment, the disease presents with features of parkinsonism as well as visual hallucinations and other characteristic neuropsychiatric symptoms. No approved treatment for DLB currently exists, although in Japan the use of acetylcholinesterase inhibitors is recommended in the treatment of the disease according to major consensus guidelines.

Clinical backing

Based on a preceding Phase II study (Study 431) of donepezil in Japanese patients with DLB, in which donepezil demonstrated significant improvement over placebo in core efficacy outcome measures such as cognitive function, behavioral and neuropsychiatric symptoms, and global function, Eisai conducted a Phase III study (Study 341) to assess the superiority of 12-week donepezil treatment over placebo in patients with DLB. The co-primary endpoints set for Study 341 were cognitive function and behavioral and neuropsychiatric symptoms. In addition, the safety and efficacy of long-term donepezil administration (52 weeks) were also investigated.

The results of Study 341 noted significant improvement in cognitive function in the donepezil groups compared to the placebo cohort at the final evaluation point after 12 weeks of treatment, and cognitive function was also observed to be maintained at a level higher than at baseline after 52 weeks of treatment. Improved behavioral and neuropsychiatric symptoms were observed in all treatment groups, both donepezil and placebo, and suggested no significant difference among groups at the final evaluation point after 12 weeks of treatment. Furthermore, adverse events (AEs) in both studies were consistent with the known safety profile of donepezil and no new or unexpected AEs occurred.

With more than 200,000 patients estimated to be living with the disease in Japan and this number expected to rise due to a rapidly aging population, the need for new DLB treatments in a clinical setting is increasing. As the originator of Aricept, Eisai is looking at the realities faced by patients with dementia in Japan and is working to further contribute to improving their quality of life (QOL) as well as the QOL of their families and caregivers.