Objective: This randomised, double-blind exploratory trial was undertaken to compare treatment effects and tolerability of EGb 761(R), donepezil and combined treatment in patients with AD and neuropsychiatric features.
Method: We enrolled 96 outpatients, aged 50 years or above, who met the NINCDS/ADRDA criteria for probable AD, scored below 36 on the TE4D, a screening test for dementia, below 6 on the Clock-Drawing Test (CDT) and between 9 and 23 on the SKT, a cross-culturally validated cognitive test battery. They scored at least five on the 12-item Neuropsychiatric Inventory (NPI). EGb 761(R) (240 mg per day), donepezil (initially 5 mg, after 4 weeks 10 mg per day) or EGb 761(R) and donepezil combined (same doses) were administered for 22 weeks.
Results: Changes from baseline to week 22 and response rates were similar for all three treatment groups with respect to all outcome measures (SKT, NPI, total score and activities-of-daily-living sub-score of the Gottfries-Bråne-Steen Scale, Hamilton Rating Scale for Depression, CDT and Verbal Fluency Test). An apparent tendency in favour of combination treatment warrants further scrutiny. Compared to donepezil mono-therapy, the adverse event rate was lower under EGb 761(R) treatment and even under the combination treatment.
Conclusion: These exploratory findings helped to develop three hypotheses that will have to be proven in further studies: (1) there is no significant difference in the efficiency between EGb 761(R) and donepezil, (2) a combination therapy will be superior to a mono-therapy with one of both substances and (3) there will be less side effects under a combination therapy than under mono-therapy with donepezil.