Effect of Age, Cognitive Impairment Severity, and Duration of Disease on Efficacy of Masupirdine in Moderate Alzheimer's Disease Patients: A Post Hoc Analysis of a Phase-2 Randomized Placebo Controlled Study Results

Abstract

Alzheimer's disease (AD) is an age-related progressive neurodegenerative brain disorder with cognitive symptoms as a hallmark phenotype of the disease. Masupirdine, a pure serotonin 6 (5-HT6) receptor antagonist is being developed for the treatment of cognitive deficits in AD. The objective of the current study is the post hoc analysis of a multicenter, randomized, double-blind, parallel group, 26-week, placebo-controlled phase-2 study (NCT02580305) that evaluated the effects of masupirdine on cognition in patients with moderate AD. Methods: Masupirdine phase 2 study included AD patients of 50 to 85 years age, mini-mental state examination (MMSE) score of 12 to 20 and diagnosis of probable AD at least 1 year prior to the screening visit. The impact of age, cognitive impairment severity, and duration of disease since diagnosis on efficacy of masupirdine as assessed by 11-item version of the Alzheimer's Disease Assessment Scale–Cognitive subscale (ADAS-Cog 11) was evaluated. Treatment effects were assessed by Cohen’s d effect size. Results: Cohen’s d effect size for change in ADAS-Cog 11 scores from baseline to week 26 ranged between ~0.2 and 0.4 for the subgroup of population with age ≤ 70 years, MMSE range of 18 to 20, and duration of disease over 4 years (since diagnosis). Conclusions: Considering the linear relationship between age and cognitive decline, masupirdine effects across the subgroups could be attributed to “slowing of cognitive decline”. The study provides important findings for design of future clinical trials. Further research is warranted to confirm the potential beneficial effects of masupirdine on cognition in AD patients.