Memantine in moderate to severe Alzheimer's disease: a meta-analysis of randomised clinical trials.

The efficacy of memantine in Alzheimer's disease (AD) has been investigated in multiple randomised, placebo-controlled phase III trials. Recently, the indication label for memantine in Europe was extended to cover patients with moderate to severe AD, i.e. Mini-Mental State Exam total scores below 20. The efficacy data for memantine in this patient subgroup has been summarised by a meta-analysis of 1,826 patients in six trials. Efficacy was assessed using measures of global status (Clinician's Interview-Based Impression of Change Plus Caregiver Input), cognition (Alzheimer's Disease Assessment Scale - Cognitive Subscale, or Severe Impairment Battery), function (Alzheimer's Disease Cooperative Study Activities of Daily Living 19- or 23-item scale), and behaviour (Neuropsychiatric Inventory). Results (without replacement of missing values) showed statistically significant effects for memantine (vs. placebo) in each domain. Memantine was well tolerated, and the overall incidence rates of adverse events were comparable to placebo. This meta-analysis supports memantine's clinically relevant efficacy in patients with moderate to severe AD.