Discovery of (2<i>S</i>,3<i>R</i>)‑<i>N</i>‑[2-(Pyridin-3-ylmethyl)-1-azabicyclo[2.2.2]oct-3-yl]benzo[<i>b</i>]furan-2-carboxamide (TC-5619), a Selective α7 Nicotinic Acetylcholine Receptor Agonist, for the Treatment of Cognitive Disorders

(2<i>S</i>,3<i>R</i>)-<i>N</i>-[2-(Pyridin-3-ylmethyl)-1-azabicyclo­[2.2.2]­oct-3-yl]­benzo­[<i>b</i>]­furan-2-carboxamide (<b>7a</b>, TC-5619), a novel selective agonist of the α7 neuronal nicotinic acetylcholine receptor, has been identified as a promising drug candidate for the treatment of cognitive impairment associated with neurological disorders. <b>7a</b> demonstrated more than a thousand-fold separation between the affinities for the α7 and α4β2 receptor subtypes and had no detectable effects on muscle or ganglionic nicotinic receptor subtypes, indicating a marked selectivity for the central nervous system over the peripheral nervous system. Results obtained from homology modeling and docking explain the observed selectivity. <b>7a</b> had positive effects across cognitive, positive, and negative symptoms of schizophrenia in animal models and was additive or synergistic with the antipsychotic clozapine. Compound <b>7a</b>, as an augmentation therapy to the standard treatment with antipsychotics, demonstrated encouraging results on measures of negative symptoms and cognitive dysfunction in schizophrenia and was well tolerated in a phase II clinical proof of concept trial in patients with schizophrenia