Selective EP1 prostanoid receptor antagonist (Ki values are 1.3, 11.2, 17.5, 61.1, > 100, > 100, > 100, >100 and > 100 μM for EP1, TP, EP3, EP2, EP4, FP and DP receptors respectively). Attenuates PGE2-induced neuronal cell death in vitro and slows tumor growth in vivo.