Casopitant (GW679769) is a novel substituted piperidine derivative that competitively binds with NK1 receptors. The full occupancy of the receptor by their piperidine compound inhibits its binding with tachykinin neurotransmitters, including SP. Casopitant, in a series of in vitro and in vivo experimentations, has exhibited a potent NK1 receptor antagonism. On 29 May 2008, GlaxoSmithKline announced the submission of a new drug application to the FDA for intravenous and oral formulations of casopitant mesylate. This drug was proposed for the prevention of chemotherapy-induced nausea and vomiting as an add-on therapy to the standard dual therapy of 5-HT3 receptor antagonists + dexamethasone. The submission also included a proposed indication for postoperative nausea and vomiting prevention. Rezonic™ is the proposed trade name for casopitant mesylate in the United States; Zunrisa™ is the proposed trade name for casopitant mesylate for GlaxoSmithKline’s global group of companies. In September 2009, GlaxoSmithKline decided to discontinue all regulatory filings for casopitant based on an estimate of the amount of additional safety data.