APD916

APD916 is a potent and selective small molecule inverse agonist of the histamine H3 receptor. It was originally discovered and developed by Arena Pharmaceuticals for the treatment of sleep-wake disorders, particularly narcolepsy with cataplexy. The drug demonstrated dose-proportional pharmacokinetics in early clinical trials, with a terminal half-life of approximately 50 hours. In preclinical studies, APD916 increased wakefulness in rodents as measured by polysomnography. Clinical development reached Phase 1 before being suspended; adverse events at higher doses included insomnia and abnormal dreams. Arena Pharmaceuticals was later acquired by Pfizer[1][2][4][5][7][8].