Benfotiamine and Cognitive Decline in Alzheimer's Disease: Results of a Randomized Placebo-Controlled Phase IIa Clinical Trial

Background: In preclinical models, benfotiamine efficiently ameliorates the clinical and biological pathologies that define Alzheimer's disease (AD) including impaired cognition, amyloid-beta plaques, neurofibrillary tangles, diminished glucose metabolism, oxidative stress, increased advanced glycation end products (AGE), and inflammation. Objective: To collect preliminary data on feasibility, safety, and efficacy in individuals with amnestic mild cognitive impairment (aMCI) or mild dementia due to AD in a placebo-controlled trial of benfotiamine. Methods: A twelve-month treatment with benfotiamine tested whether clinical decline would be delayed in the benfotiamine group compared to the placebo group. The primary clinical outcome was the Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog). Secondary outcomes were the clinical dementia rating (CDR) score and fluorodeoxyglucose (FDG) uptake, measured with brain positron emission tomography (PET). Blood AGE were examined as an exploratory outcome. Results: Participants were treated with benfotiamine (34) or placebo (36). Benfotiamine treatment was safe. The increase in ADAS-Cog was 43% lower in the benfotiamine group than in the placebo group, indicating less cognitive decline, and this effect was nearly statistically significant (p = 0.125). Worsening in CDR was 77% lower (p = 0.034) in the benfotiamine group compared to the placebo group, and this effect was stronger in the APOE epsilon 4 non-carriers. Benfotiamine significantly reduced increases in AGE (p = 0.044), and this effect was stronger in the APOE epsilon 4 non-carriers. Exploratory analysis derivation of an FDG PET pattern score showed a treatment effect at one year (p = 0.002). Conclusion: Oral benfotiamine is safe and potentially efficacious in improving cognitive outcomes among persons with MCI and mild AD.