Efficacy and safety of Tianmabianchunzhigan in mild to moderate vascular dementia: Protocol of a randomized controlled IIa trial

BACKGROUND: Vascular dementia (VaD) is the 2nd most common subtype of dementia after Alzheimer disease. Currently, there are no medications approved for treating patients with VaD. Tianmabianchunzhigan (TMBCZG) tablet is an active ingredient extracted from Gastrodia that has been reported to improve memory and other cognition. And the TBMCZG has been approved clinical trial with patients with VaD by center for drug evaluation of China (CFDA). To evaluate the efficacy, safety, and tolerability of TMBCZG tablets in the treatment of mild to moderate VaD, we designed and reported the methodology for a 24-week, randomized, double-blind, parallel, placebo-controlled, multicenter trial. METHODS: A total of 160 patients with mild to moderate VaD will be enrolled. After a 2-week run-in period, the eligible patients will be randomized to receive either TMBCZG high-dose group (TBMCZG 3 tablets, twice per day); TMBCZG middle-dose group (TMBCZG 2 tablets and placebo 1 tablet twice per day); TMBCZG low-dose group (TMBCZG 1 tablet and placebo 2 tablets, twice per day); placebo group (placebo 3 tablets, twice per day) for 24 weeks, with a follow-up 12 weeks after withdrawn drug treatment. The primary efficacy measurement will be the vascular dementia assessment scale-cognitive subscale and the Clinical Dementia Rating-Sum of the Boxes scale. The secondary efficacy measurements will include the mini mental state examination and activities of daily living. Adverse events will also be reported. DISCUSSION: This randomized trial will be the 1st rigorous study on the efficacy and safety of TMBCZG tablets for treating cognitive symptoms in patients with VaD using a rational design. TRIAL REGISTRATION: ClinicalTrials.gov NCT03230071. Registered on July 26, 2017.