Potent and selective CCR3 antagonist (IC50 = 4 nM). Displays > 2500-fold selectivity over C5aR, LTD4, CCR7, CXCR1 and CXCR2 receptors. Inhibits eotaxin-, eotaxin-2- and MCP-4-induced Ca2+ mobilization (IC50 values are 38, 35 and 20 nM respectively) and inhibits eotaxin-, eotaxin-2- and MCP-4-induced eosinophil chemotaxis with similar potencies.