&NA;Zatosetron (LY 277359, LY 19167) is a serotonin 5-HT3receptor antagonist undergoing phase III clinical trials with Eli Lilly in the US for treatment of chronic anxiety. Phase II trials in Japan have been discontinued. Zatosetron has also shown promise as an antiemetic agent and is undergoing phase II trials in the US for this indication. AUS phase II clinical trial of zatosetron failed to demonstrate significant improvement in patients with migraine when the drug was administered as a single IV infusion.