Itaru Arimoto

Donepezil treatment of patients with severe Alzheimer's disease in a Japanese population: results from a 24-week, double-blind, placebo-controlled, randomized trial.

Background/Aims: A 24-week, randomized, parallel-group, double-blind placebo-controlled study was conducted to evaluate the efficacy and tolerability of donepezil in severe Alzheimer’s disease (AD). Methods: Patients with severe AD (Mini-Mental State Examination score 1–12; modified Hachinski Ischemic Score ≤6; Functional Assessment Staging ≧6) were enrolled in this study in Japan. A total of 325 patients were randomized to donepezil 5 mg/day (n = 110), donepezil 10 mg/day (n = 103) or placebo (n = 112). Primary outcome measures were change from baseline to endpoint in the Severe Impairment Battery (SIB) and Clinician’s Interview-Based Impression of Change-plus caregiver input (CIBIC-plus) at the endpoint visit. Results: Donepezil 5 mg/day and 10 mg/day were significantly superior to placebo on the SIB, with a least-squares mean treatment difference of 6.7 and 9.0, respectively (p < 0.001 compared with placebo). CIBIC-plus analyses showed significant differences in favor of donepezil 10 mg/day over placebo at endpoint (p = 0.003). A statistically significant dose-response relationship was demonstrated with the SIB and CIBIC-plus. Donepezil was well tolerated. Conclusion: This study confirmed the effectiveness of donepezil 10 mg/day in patients with severe AD and demonstrated a significant dose-response relationship. Donepezil at dosages of both 5 mg/day and 10 mg/day is safe and well tolerated in Japanese patients with severe AD.

Long-term safety and efficacy of donepezil in patients with severe Alzheimer's disease: results from a 52-week, open-label, multicenter, extension study in Japan.

Background/Aims: A 6-month, randomized, double-blind, placebo-controlled study was extended to evaluate long-term safety and efficacy of donepezil in community-dwelling Japanese patients with severe Alzheimer’s disease (AD). Methods: 189 patients were enrolled from the double-blind study into a 52-week, open-label extension study. After a 2- to 8-week washout, donepezil was escalated within 6 weeks to 10 mg/day. Main outcomes were Severe Impairment Battery (SIB), Alzheimer’s Disease Cooperative Study-Activities of Daily Living scale for severe AD (ADCS-ADL-sev) and Behavioral Pathology in Alzheimer’s Disease Rating Scale (BEHAVE-AD). Safety parameters were monitored throughout. Results: Overall, mean change from extension study baseline in SIB scores improved until week 24; however, scores were influenced by prior treatment during the double-blind study and by length of washout. Patients treated with donepezil retained some treatment benefits after a washout of 2–4 weeks but lost all treatment benefits after a washout of 4–8 weeks. There was no change in ADCS-ADL-sev or BEHAVE-AD scores. Adverse events were consistent with the known donepezil safety profile. Conclusion: Donepezil is effective and safe for symptomatic treatment of severe AD for at least 1 year. Patients who receive donepezil 10 mg daily with little or no interruption achieve the best long-term outcome.