Alzheimer’s Drug Fails Mid-Stage Study
TC-1734 not superior to donepezil, researchers find
Disappointing results have been reported from a phase IIb monotherapy clinical trial of TC-1734 (Targacept, Inc.) as a treatment for mild-to-moderate Alzheimer’s disease (AD). The investigational compound is a small molecule that acts selectively on the alpha4beta2 neuronal nicotinic receptor (NNR) subtype.
TC-1734 did not meet the study’s objective of showing superiority over donepezil (Aricept, Eisai/Pfizer), the marketed medication most often prescribed for AS, after 52 weeks of treatment. The trial did not include a placebo arm and was not designed to determine whether TC-1734 is equivalent to donepezil. The co-primary endpoints for the study were measures of cognitive function and global function.
The double-blind, positive-comparator, randomized, parallel-group trial evaluated TC-1734 head-to-head against donepezil in 293 patients with AD. For U.S. regulatory purposes, the Alzheimer’s Disease Assessment Scale–Cognitive subscale 11-item assessment and the Clinician Interview-Based Impression of Change Plus Caregiver Input (CIBIC) were co-primary endpoints. The study included a 3-week screening period, followed by a 12-month treatment period, during which patients received a fixed dose of TC-1734 (30 mg) or donepezil once daily.
Based on the trial results, Targacept will not invest in further development of this compound.