JNJ-39758979 is a selective, orally active, and high-affinity histamine H4 receptor antagonist with Kis of 12.5, 5.3, and 25 nM for human, mouse, and monkey histamine H4 receptor, respectively. JNJ-39758979 functionally antagonizes histamine-induced cAMP inhibition with a pA2 of 7.9 in transfected cells. JNJ-39758979 shows good anti-inflammatory and antipruritic activity.