Potent chemokine receptor 1 (CCR1) antagonist (IC50 values are 0.9 and 5.8 nM for human and mouse CCR1 receptors respectively). Also displays high selectivity for human but not mouse CCR3 receptors (IC50 values are 0.58 and 460 nM respectively). Improves paw inflammation, joint damage and dramatically reduces cell infiltration into joints in collagen-induced arthritis in mice. Isomer of UCB 35625 (Cat. No. 2757).