A 24-week open-label extension study of memantine in moderate to severe Alzheimer disease.

Background: This study is an extension of a 28-week, randomized, double-blind, placebo-controlled study of memantine in 252 patients with moderate to severe Alzheimer disease.

Objective: To evaluate long-term memantine treatment in moderate to severe Alzheimer disease.

Design, Setting, And Patients: Open-label, 24-week extension trial. Raters remained blind to the patients' initial study treatment. Patients (n = 175) were enrolled from the previous double-blind study in an outpatient setting.

Intervention: Twenty mg of memantine was given daily.

Main Outcome Measures: Efficacy assessments from the double-blind study were continued and safety parameters were monitored.

Results: Patients who switched to memantine treatment from their previous placebo therapy experienced a significant benefit in all main efficacy assessments (functional, global, and cognitive) relative to their mean rate of decline with placebo treatment during the double-blind period (P<.05). The completion rate for the extension phase of the study was high (78%) and the favorable adverse event profile for memantine therapy was similar to that seen in the double-blind study.

Conclusion: These results extend previous findings that demonstrated the efficacy and safety of memantine in the treatment of patients with moderate to severe Alzheimer disease.