Impact of study design and patient population on outcomes from cholinesterase inhibitor trials.

The authors conducted a comparative review of study designs and patient populations used in pivotal trials investigating various cholinesterase inhibitors (tacrine, donepezil, rivastigmine, galantamine, controlled-release physostigmine, and metrifionate) and their impact on outcomes reported. Study design parameters that were investigated included patient selection, definitions of adverse dropouts and serious adverse events, effective doses used, dosing flexibility (fixed versus flexible), forced titration, and titration rate. Population characteristics included medical comorbidity and disease severity.

Long-term effects of rivastigmine in moderately severe Alzheimer's disease: does early initiation of therapy offer sustained benefits?

Goals of the study included evaluating the long-term efficacy of rivastigmine in Alzheimer's disease (AD) patient categories stratified by baseline dementia severity, and post hoc investigation of particular benefits of early initiation of rivastigmine treatment in moderately severe AD. Both rivastigmine-treated groups (originally randomized to 1-4 or 6-12 mg/day) experienced significantly smaller declines in Alzheimer's Disease Assessment Scale-Cognitive subscale (ADAS-Cog) scores from baseline than the projected placebo group after 52 weeks. Patients receiving rivastigmine from Day 1 experienced significantly less decline compared with patients originally receiving placebo and then initiating rivastigmine treatment after a 6-month delay.