A 24-week randomized, controlled trial of memantine in patients with moderate-to-severe Alzheimer disease

Area of Science:

• Neuroscience
• Clinical Pharmacology
• Geriatrics

Background:

• Alzheimer disease (AD) is a progressive neurodegenerative disorder.
• Current treatments, including cholinesterase inhibitors, offer symptomatic relief but do not halt disease progression.
• Memantine, an NMDA receptor antagonist, is used for moderate-to-severe AD, often in combination therapy.

Purpose of the Study:

• To evaluate the efficacy and safety of memantine monotherapy in patients with moderate-to-severe Alzheimer disease (AD).
• To compare memantine (20 mg/d) versus placebo in patients not receiving a cholinesterase inhibitor.

Main Methods:

• A 24-week, double-blind, placebo-controlled trial involving 350 patients.
• Primary outcome measure: Severe Impairment Battery (SIB).
• Secondary outcome measures: Alzheimer's Disease Cooperative Study-Activities of Daily Living Scale (ADCS-ADL19) and Clinician's Interview-Based Impression of Change plus Caregiver Input (CIBIC-Plus).

Main Results:

• Memantine did not demonstrate statistically significant benefit over placebo on the SIB at the week 24 endpoint in prospectively defined analyses.
• Significant advantages for memantine were observed at weeks 12 and 18 on the SIB and CIBIC-Plus, but not at week 24.
• Nonparametric analyses showed a statistically significant benefit for memantine on the SIB at week 24, but not on the ADCS-ADL19. Adverse event profiles were similar between groups.

Conclusions:

• Memantine monotherapy showed limited statistically significant long-term efficacy in moderate-to-severe Alzheimer disease patients in this trial.
• Early trends favoring memantine did not persist to the primary endpoint.
• Further research may be needed to clarify the role of memantine monotherapy in specific patient subgroups or disease stages.