J-113863 is a potent and selective CCR1 antagonist with species-specific activity, showing high affinity for human CCR1 (IC50 0.9 nM) and mouse CCR1 (IC50 5.8 nM). It also antagonizes human CCR3 but is much less active on the mouse ortholog, and is inactive against several other chemokine and inflammatory receptors. This profile makes it a valuable research tool for studying CCR1-mediated pathways in inflammation, autoimmunity, and fibrosis in both cellular and animal models.
