A multicentre, randomized, double-blind, placebo-controlled study to evaluate the efficacy, tolerability and safety of two doses of metrifonate in patients with mild-to-moderate Alzheimer's disease: the MALT study

Background: Metrifonate is a long-lasting acetylcholinesterase inhibitor being developed for the symptomatic treatment of Alzheimer's disease (AD).

Objectives: This study compared the efficacy, tolerability and safety of two doses of metrifonate in patients with mild-to-moderate AD, over a 26-week treatment period.

Methods: Six hundred and five patients were randomized to placebo (n=208), a 40/50 mg dose (40 or 50 mg by weight; n=200) or a 60/80 mg dose (60 or 80 mg by weight; n=197) metrifonate. Patients randomized to receive metrifonate were administered a once-daily loading dose of 80 or 120 mg based on weight for 2 weeks, followed by the relevant maintenance dose for 24 weeks. Four main clinical domains of AD were assessed: cognition (ADAS-cog and MMSE), psychiatric and behavioural symptoms (ADAS-noncog and NPI), instrumental and basic activities of daily living (DAD) and global functioning (CIBIC-plus, CIBIS-plus and GDS).

Results: ADAS-cog performance was significantly improved in the 60/80 mg and 40/50 mg dose groups, compared with placebo, in the intention-to-treat (ITT) population. In addition, statistically significant treatment differences were demonstrated between the 60/80 mg dose group and placebo on MMSE, ADAS-noncog, the NPI subitems of hallucinations and apathy, DAD, CIBIC-plus, CIBIS-plus and the GDS. The performance of the 40/50 mg dose group was also significantly superior to placebo on the CIBIS-plus and the NPI subitem aberrant motor behaviour.

Conclusions: Metrifonate significantly improved a wide range of symptoms across all four clinical domains of AD in a dose-dependent manner, and was safe and well tolerated at both doses studied.