Ginkgo biloba extract EGb 761(R), donepezil or both combined in the treatment of Alzheimer's disease with neuropsychiatric features: a randomised, double-blind, exploratory trial.

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.