Phase 3 solanezumab trials: Secondary outcomes in mild Alzheimer's disease patients.

Introduction: EXPEDITION and EXPEDITION2 were identically designed placebo-controlled phase 3 studies assessing effects of solanezumab, an antiamyloid monoclonal antibody binding soluble amyloid-β peptide, on cognitive and functional decline over 80 weeks in patients with mild-to-moderate Alzheimer's disease (AD). Primary findings for both studies have been published.

Methods: Secondary analyses of efficacy, biomarker, and safety endpoints in the pooled (EXPEDTION + EXPEDITION2) mild AD population were performed.

Results: In the mild AD population, less cognitive and functional decline was observed with solanezumab (n = 659) versus placebo (n = 663), measured by Alzheimer's Disease Assessment Scale Cognitive subscale, Mini-Mental State Examination, and Alzheimer's Disease Cooperative Study-Activities of Daily Living functional scale Instrumental ADLs. Baseline-to-endpoint changes did not differ between treatment groups for Alzheimer's Disease Cooperative Study-Activities of Daily Living functional scale, basic items of the ADCS-ADL, and Clinical Dementia Rating Sum of Boxes. Plasma/cerebrospinal fluid biomarker findings indicated target engagement by solanezumab. Solanezumab demonstrated acceptable safety. Efficacy findings for the moderate AD population are also provided.

Discussion: These findings describe solanezumab effects on efficacy/safety measures in a mild AD population. Another phase 3 study, EXPEDITION3, will investigate solanezumab's effects in a mild AD population.