There has been more disappointment in the search for effective Alzheimer's disease treatments after Spain's Zeltia announced results from a mid-stage trial of tideglusib.

The Madrid-headquartered firm's Noscira unit says that the primary cognitive endpoint and two of the secondary endpoints were not met in the 26-week ARGO Phase IIb trial. This study evaluated the efficacy of tideglusib versus placebo plus standard of care for the treatment of mild-to-moderate AD.

The company noted that tideglusib, a glycogen synthase kinase 3 (GSK-3) inhibitor, was "relatively well-tolerated" in the 306-patient study and no new safety concerns were detected. No decision regarding future development has yet been taken as Zeltia says pending analyses of the other secondary end-points, subpopulations, biomarkers and a magnetic resonance image substudy will be completed in the coming weeks.

It is a blow for Zeltia given that in experimental models, tideglusib (also known as NP-12), the only GSK-3 inhibitor nowadays in clinical development for AD, "has demonstrated ability to act on the most relevant histopathological lesions associated with AD-reducing tau protein phosphorylation, accumulation of amyloid plaques in the brain, oligomeric amyloid toxicity, neuritic dystrophies, and hippocampal and entorhinal cortex neuron loss", the company says. It also helped to improve spatial memory deficit and provides neuroprotection in vivo; it also has "a potent anti-inflammatory effect in a range of animal models".