Potent and selective CCR4 antagonist (pIC50 = 7.8). Exhibits no activity at CXCR1 and CXCR2, CCR1, CCR2b, CCR5, CCR7, and CCR8 at 10 μM, and no significant activity when screened against a panel of 120 receptors and enzymes. Inhibits CCL22 Ca2+ response and Th2 cell CCL17/22 driven chemotaxis in vitro. Inhibits lung inflammation following antigen challenge in ovalbumin- sensitized rats. Purity 98%. MW (observed): 334.18