Abstract
In this post hoc analysis, sustained cognitive improvement was assessed in a 24-week, randomized, placebo-controlled trial of once-daily, extended-release (ER) memantine (28 mg) in ChEI-treated patients with moderate to severe AD. Five positive SIB response levels to double-blind treatment were selected (improvements of ≥0, ≥5, ≥10, ≥15, and ≥20 points), corresponding to 0-2 standard deviations (SDs) of the observed baseline-to-endpoint score change. Numbers of patients in each group who attained such responses at weeks 4, 8, 12, or 18 and maintained them through week 24 were compared using Fisher’s exact test. Significantly more memantine ER-treated than placebo-treated patients maintained week 8 SIB responses of ≥5 points (26.1% vs 17.0%; P = 0.014) and ≥10 points (14.6% vs 7.6%; P = 0.012) through week 24. Similar results were observed for sustained responses obtained at week 12 (≥5 points: 28.5% vs 19.9%, P = 0.025; ≥10 points: 16.3% vs 8.2%, P = 0.005; ≥15 points: 9.5% vs 4.1%, P = 0.015) and week 18 (≥10 points:18.8% vs 10.0%, P = 0.004; ≥15 points: 10.9% vs 4.5%, P = 0.006). In conclusion, memantine ER was associated with cognitive improvement attained after 8-18 weeks and sustained through week 24.