Disease progression model using the integrated Alzheimer's Disease Rating Scale

Abstract

Introduction: An Alzheimer's disease (AD) dementia disease progression model was developed based on the integrated Alzheimer's Disease Rating Scale (iADRS).

Methods: Data from 3483 placebo participants in six AD trials were used to develop the disease progression model with NONMEM (version 7.4.2) and examined for mild cognitive impairment, and mild and moderate dementia due to AD.

Results: Baseline iADRS score was significantly influenced by AD symptomatic medication use, EXPEDITION2 enrollment (included moderate AD participants), age, and baseline Mini-Mental State Examination (MMSE) score. Rate of disease progression increased across disease stage and was significantly influenced by AD medication use, age, and baseline MMSE score. Apolipoprotein E ε4 carrier status did not influence baseline iADRS score or disease progression.

Discussion: These results demonstrate a disease progression model describing the time course of the iADRS across the AD severity spectrum. This model can assist future clinical trials in study design optimization and treatment effect interpretation.

Highlights: A disease progression model described the integrated Alzheimer's Disease Rating Scale (iADRS) time course in mild cognitive impairment to moderate Alzheimer's disease. Using the linear regression model, iADRS scores can be calculated for Mini-Mental State Examination scores. Results can help optimize future clinical trial design and aid in understanding treatment effects.

Keywords: Alzheimer's disease; cognitive/functional endpoint; disease progression; integrated Alzheimer's Disease Rating Scale; nonlinear mixed effects modeling; quantitative method.