Is memantine a breakthrough in the treatment of moderate-to-severe Alzheimer's disease?

Over stimulation of the NMDA receptor by glutamate has long been considered to have a role in Alzheimer's disease (AD). Memantine, a non-competitive antagonist of NMDA receptors, has recently been tested in moderate-to-severe AD. At 28 weeks, there was a small significant mean difference of 0.3 in favour of memantine, showing benefit in the Clinician's Interview-Based Impression of Change Plus Caregiver Input (CIBIC-Plus) global score. The other primary efficacy variable was the Alzheimer's disease Cooperative Study Activities of Daily Living Inventory, modified for more severe dementia (ADCS-ADL-sev) and there was significantly less deterioration in the ADCS-ADL-sev score in the memantine group than in the placebo group (2.1 versus 3.4, respectively). As there are no drugs commonly used for their effectiveness in moderate-to-severe AD, any drug that causes a benefit, however small, as memantine has been shown to do in this trial, represents a breakthrough.