Idalopirdine, also known as Lu AE58054 or Iladopirdine, is a potent and selective 5-HT6 receptor antagonist under development by Lundbeck as an augmentation therapy for the treatment of cognitive deficits associated with Alzheimer's disease and schizophrenia. It is in phase III clinical trials. Lu AE58054 displayed high affinity to the human 5-HT(6) receptor (5-HT(6)R) with a Ki of 0.83 nm. Lu AE58054 demonstrated >50-fold selectivity for more than 70 targets examined. Lu AE58054 is a selective antagonist of 5-HT(6)Rs with good oral bioavailability and robust efficacy in a rat model of cognitive impairment in schizophrenia. Lu AE58054 may be useful for the pharmacotherapy of cognitive dysfunction in disease states such as schizophrenia and Alzheimer's disease.