A Double-Blind, Randomized, Placebo Controlled Study to Evaluate the Efficacy and Safety of DCB-AD1 in Patients With Mild to Moderate Alzheimer's Disease

The growing number of patients with dementia has become a great concern of many aging societies. Up to this moment no treatment can stop Alzheimer's dementia (AD), thus, developing new treatments are still mandatory. In this study we will investigate a new drug DCB-AD1, an herbal medicine derived from root of Fo-ti. Historically the Chinese used the Fo-ti root for its rejuvenating properties to treat premature aging, weakness and so on. In DCB (Development Center of Biotechnology)'s preliminary studies using human neuroblastoma cell, SK-N-SH, Fo-ti water extracts exhibited high potential in preventing A-beta and hydrogen peroxide-induced cell death. From two different AD animal models, DCB have observed neuroprotection effects of Fo-ti using water maze and hole-board exploration tests, Though the pharmacological effect of Fo-ti has yet been clarified, its protective effect may result from radical scavenging activities, anti-inflammatory effect or anti-peroxidation. We intend to investigate DCB-AD1 on its cognitive and neurophysiological effects on Alzheimer disease through a randomized, double-blind, placebo-controlled therapeutic trial for 24 weeks. We will complete 80 eligible cases for analysis in this clinical trial with 40 in each investigation site. The estimated drop-out rate is around 25~30 %. Patients are eligible if they fulfill criteria for a diagnosis of probable AD of NINCDS-ADRDA. We will include patients with Mini-Mental State Examination scores of 12~24 and Clinical Dementia Rating 1 or 2. Patients will be allowed to take cholinesterase inhibitors, donepezil, rivastigmine, galantamine or memantine if the dose has been unchanged for the last 3 months before the study entry and remains stable during the 24-week study period.

As for the outcome measures, the primary end point will be the score changes of ADAS-Cog at the end of treatment from the baseline. Secondary end points include CIBIC-PLUS, IADL, Behav-AD, MMSE and CDR.

The statistic analysis will be on both intention-to-treat and completed cases. Because of the limitation of the sample size we would expect but a positive trend of the efficacy unless the effect size of DCB-AD1 is larger than 0.63. This information will provide us clue if further clinical investigation such as a phase III study should be carried out in an even larger scale. We will valuable experience on the adverse effect of prolonged (24-week) use of Fo-ti.