BCHE and Alzheimer disease: In this 24-week, double-masked, parallel, randomized, controlled clinical study, the efficacy and tolerability of Souvenaid was investigated in 527 persons with mild-to-moderate AD taking stable doses of US Food and Drug Administration-approved symptomatic AD treatments (that is, cholinesterase inhibitors and/or memantine), using the ADAS-cog as the primary outcome measure.