A randomized double-blind study comparing 25 and 50 mg TC-1734 (AZD3480) with placebo, in older subjects with age-associated memory impairment

Abstract

Cognitive decline is a feature of ageing and can be defined as normal (age-associated memory impairment) or pathological (mild cognitive impairment/Alzheimer’s disease). Stimulation of selective brain-specific neuronal nicotinic acetylcholine receptors might offer symptomatic treatment for normal ageing. The objective of this study was to assess the safety, tolerability and efficacy of TC-1734 (AZD3480), a selective α4β2 nicotinic agonist, in the treatment of age-associated memory impairment. A randomized placebo-controlled trial was conducted in 16 community-based centers within the USA. Subjects who met objective criteria for age-associated memory impairment were recruited between November 2004 and December 2005. Subjects were randomly assigned to receive orally 25 mg ( n = 59), 50 mg ( n = 68) TC-1734 (AZD3480) or placebo ( n = 66) in a double-blind fashion for 16 weeks. Main outcome measures included routine clinical safety measures, tolerability, cognitive assessment via the Cognitive Drug Research computerized test battery and a Subject Global Impression Scale of Cognition (SCI-Cog). Two outcomes from the computerized test battery – a factor assessing attention and one assessing episodic memory, along with the SGI-Cog were defined as co-primary outcome variables. Baseline to Week 16 differences from placebo for 50 mg TC-1734 (AZD3480) were considered of primary importance. For 50 mg TC-1734 (AZD3480) attention factor the mean drug–placebo difference was 22.9 (95% confidence interval 4.8 to 41.4) p = 0.01 for episodic memory factor the difference was −7.6 (95% confidence interval −14.4 to −0.8), p = 0.029, and for the SGI-Cog the difference was 0.99 (95% confidence interval 0.2 to 1.8), p = 0.015. As all three co-primary outcomes were positive it can be concluded the compound likely had a beneficial effect on cognition. TC-1734 (AZD3480) appeared safe and well tolerated in this study.