DELAYED-START ANALYSES IN THE PHASE 3 SOLANEZUMAB EXPEDITION3 STUDY IN MILD ALZHEIMER’S DISEASE
H. Liu-Seifert, M.G. Case, S.W. Andersen, K.C. Holdridge, P.S. Aisen, S. Kollack-Walker, E. Siemers
J Prev Alz Dis 2018;5(1):8-14
OBJECTIVE: A delayed-start design has been proposed to assess a potential disease-modifying effect in investigational drugs for Alzheimer’s disease that target the underlying disease process. We extended this methodology to recently obtained data from the EXPEDITION3.
METHODS: EXPEDITION3 was a Phase 3, double-blind study with participants randomized to solanezumab (400 mg) or placebo every 4 weeks for 80 weeks, with an optional extension of active treatment. The delayed-start analysis was designed to determine if a statistically significant treatment difference established during the placebo-controlled period is maintained (at predefined level) during the delayed-start period, which would suggest the active drug has a disease-modifying effect. The delayed-start analysis was assessed across multiple efficacy measures, and includes data from baseline in the placebo-controlled period and up to 9 months in the delayed-start period.
RESULTS: No significant difference was observed between the placebo and solanezumab treatment groups at the end of the placebo-controlled period for the Alzheimer’s Disease Assessment Scale-Cognitive 14-item subscale. A significant treatment difference was observed at the end of the placebo-controlled period for the Alzheimer’s Disease Cooperative Study-Activities of Daily Living instrumental items, an effect also seen at 6 months in the delayed-start period, and the noninferiority criterion was met. No other efficacy measures met these criteria.
CONCLUSIONS: Delayed-start statistical methodology was used to understand the longitudinal outcomes in EXPEDITION3 and its extension. The small treatment differences observed at the end of the placebo-controlled phase prevented adequate assessment of any putative disease modifying effect.
H. Liu-Seifert ; M.G. Case ; S.W. Andersen ; K.C. Holdridge ; P.S. Aisen ; S. Kollack-Walker ; E. Siemers (2018): Delayed-Start Analyses in the Phase 3 Solanezumab EXPEDITION3 Study in Mild Alzheimer’s Disease. The Journal of Prevention of Alzheimer’s Disease (JPAD). http://dx.doi.org/10.14283/jpad.2018.1