Efficacy and Safety of a Transdermal Donepezil Patch in Patients with Mild to Moderate Alzheimer’s Disease: Open-Label, Extension Study

Background: In Japan, only oral formulation of donepezil hydrochloride is approved for the treatment of Alzheimer’s disease. Objective: To evaluate safety and efficacy of a donepezil patch 27.5 mg application for 52 weeks in patients with mild-to-moderate Alzheimer’s disease; and to evaluate safety on switching from donepezil hydrochloride tablets. Methods: This 28-week, open-label study (jRCT2080224517) is an extension of a 24-week double-blind (donepezil patch 27.5 mg versus donepezil hydrochloride tablet 5 mg) noninferiority study. The patch group (continuation group) continued administration of the patch and the tablet group (switch group) switched to the patch in this study. Results: A total of 301 patients participated (156 patients continued using patches; 145 patients switched). Both groups showed similar course on the Alzheimer’s Disease Assessment Scale-cognitive component-Japanese version (ADAS-Jcog) and ABC dementia scales. At weeks 36 and 52, changes in ADAS-Jcog from week 24 [mean (standard deviation)] were 1.4 (4.8) and 2.1 (4.9) in the continuation group, and 1.0 (4.2), and 1.6 (5.4) in the switch group. The incidence of adverse events at application site in the continuation group over 52 weeks was 56.6% (98/173). Erythema, pruritus, and contact dermatitis at application site were observed in more than 10 patients each. There was no additional adverse event of clinical concern, and no increase in their incidence from the double-blind study. During the four weeks following switching, no patient discontinued or suspended administration due to adverse events. Conclusion: Application of the patch for 52 weeks was well tolerated and feasible, including switching from tablets.