&NA;RS 8359 is a highly selective and reversible monoamine oxidase type A (MAO-A) inhibitor. RS 8359 is currently undergoing phase II clinical trials in Germany and phase I clinical trials in Japan with Sankyo as a potential antidepressant agent.The selectivity of RS 8359 for MOA-A is markedly greater than that of moclobemide. Early small-scale clinical studies, however, have not yet demonstrated any obvious efficacy or tolerability advantages with RS 8359 compared with moclobemide in the clinical setting.