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Background: Previous studies have investigated associations between apolipoprotein E (APOE)-ɛ4 allele status and acetylcholinesterase inhibitor treatment response in patients with Alzheimer’s disease. The ability to draw definitive conclusions regarding the effect of APOE-ɛ4 genotype on treatment response has been hindered by inconsistent results among studies and methodological limitations that restrict interpretation of study findings. Objective: To determine whether APOE-ɛ4 carrier status influences the magnitude of change in 13-item Alzheimer’s Disease Assessment Scale−Cognitive Subscale (ADAS-cog) score associated with acetylcholinesterase inhibitor treatment (i.e., donepezil). Methods: Analyses were performed using pooled data from the donepezil and placebo treatment arms of three consecutive, similarly designed, 12-week, multi-national, randomized clinical studies that enrolled patients with mild-to-moderate Alzheimer’s disease. Correlations between APOE-ɛ4 carrier status and ADAS-cog scores were evaluated using analysis of covariance. Results: No appreciable interaction between donepezil response and APOE-ɛ4 carrier status or copy number was detected. Both carriers and non-carriers of APOE-ɛ4 who received donepezil experienced significant improvements from baseline in ADAS-cog score versus placebo (p < 0.05). Change from baseline to final observation in the donepezil treatment group was – 2.95 for APOE-ɛ4 carriers and – 4.09 for non-carriers (p = 0.23). In contrast, non-carriers of APOE-ɛ4 in the placebo treatment group exhibited a greater improvement from baseline versus carriers (–2.38 versus – 0.60, p = 0.05). Conclusion: Within this population, APOE genotype had no statistically significant effect on cognitive response to donepezil treatment; however, APOE-ɛ4 allele status was associated with a difference in the magnitude of the change in ADAS-cog of placebo-treated patients.

BACKGROUND Levodopa-carbidopa intestinal gel (LCIG) is delivered continuously via intrajejunal percutaneous gastrostomy tube. OBJECTIVE To examine long-term safety, efficacy and quality of life of LCIG in an open-label extension study. METHODS Patients received 52 weeks of open-label LCIG treatment following a 12-week double-blind, double-dummy trial in which they were randomized to either LCIG or immediate-release oral levodopa-carbidopa. Patient cohort designation was by receipt of LCIG in the preceding trial randomization (continuing-LCIG vs. LCIG-naive patients). RESULTS Sixty-two of 66 subjects in the double-blind proceeded to the open-label extension. Most subjects (95%) reported ≥1 adverse event (AE); only 3 subjects (4.8%) discontinued due to AEs. AE incidence declined gradually over 52 weeks. Serious AEs were reported by 23%. LCIG-naive patients (N = 29) showed a decrease in "Off" time and an increase in "On" time without troublesome dyskinesia (change from baseline to final visit in mean [SD] hours = -2.34 [2.78] P < 0.001 and 2.19 [3.70] P = 0.005, respectively), while continuing-LCIG patients (N = 33) showed sustained "Off" time duration and further improvement in "On" time without troublesome dyskinesia (-0.42 [2.67] P = 0.377 and 1.00 [2.58] P = 0.036, respectively). The majority of patients in both groups (LCIG-naive, continuing-LCIG, respectively) were rated 'Much Improved' or 'Very Much Improved' at final visit on the Clinical Global Impression-Improvement scale (69.0%, 69.7%). CONCLUSIONS Continuing-LCIG patients continued to derive benefit from LCIG while the magnitude of improvement among LCIG-naive patients was similar to that observed for patients on LCIG in the preceding double-blind study. The overall AE profile was consistent with previous phase 3 clinical trials involving the LCIG system.