LY315920 is an inhibitor of human group IIA (hGIIA) secretory phospholipase A2 (sPLA2; IC50 = 9 nM). It also potently inhibits human GIIE and GX isoforms, as well as the corresponding mouse isoforms, but poorly inhibits other PLA2 enzymes. LY315920 inhibits sPLA2-induced release of thromboxane A2 from isolated guinea pig lung bronchoalveolar lavage cells (IC50 = 0.79 μM). Intravenous or oral administration of LY315920 to transgenic mice expressing human sPLA2 inhibits serum sPLA2 activity in a dose-related manner over four hours.