Abstract
Objective: To examine Severe Impairment Battery (SIB) score changes (improvement or worsening) of ≥5, ≥10, and ≥15 points for patients with moderate to severe Alzheimer’s disease (AD) receiving memantine ER (MemER)/cholinesterase inhibitors (ChEI) vs placebo (PBO)/ChEI. Background: Rigorous phase 3 studies demonstrated memantine efficacy, in combination with ChEI, on cognition, function, and global outcomes in patients with moderate-to-severe AD. In a randomized, double-blind, PBO-controlled study (NCT00322153, MemER/ChEI treatment significantly improved SIB scores vs PBO/ChEI, with a PBO-adjusted mean difference of 2.6 points at week 24. Design/Methods: Post hoc analyses examined SIB baseline-to-endpoint (week 24) score changes in patients receiving an ChEI randomized to MemER (28 mg/day) or PBO. SIB score changes were examined in 5-point increments (eg, absolute changes of 1–5, 6–10, 11–15). “Improvement/decline” was noted at 5-point changes; “notable improvement/decline” at 10-point changes; and “remarkable improvement/decline” at 15-point changes. Results: Of 676 patients (safety population), 541 had SIB scores at baseline and week 24 (n=270 MemER/ChEI; n=271 PBO/ChEI). At week 24, 40% of MemER/ChEI patients experienced a ≥5-point SIB improvement vs 31% of PBO/ChEI patients. More MemER/ChEI patients had notable improvements of ≥10 points vs PBO/ChEI patients (23% vs 13%); twice as many had remarkable improvements (≥15 points) with MemER/ChEI vs PBO/ChEI (14% vs 7%). Fewer MemER/ChEI patients declined by ≥5 points vs PBO/ChEI (19% vs 24%), with similar results at declines of ≥10 (10% vs 13%) and ≥15 (6% vs 7%). Conclusions: Compared with PBO/ChEI, more MemER/ChEI-treated patients experienced improvements of ≥5, ≥10 and ≥15 points on the SIB, all greater than the PBO-adjusted mean of 2.6 points; fewer MemER/ChEI-patients experienced a decline in cognition. As no disease-modifying AD treatments are available, these data reaffirm the efficacy of combination therapy with MemER/ChEI on cognition and support its use in patients with moderate to severe AD.