JNJ-39758979 is metabolically stable (t1/2 >120 min) when incubated in vitro with human, rat, dog, or monkey liver microsomes. JNJ 39758979 is a selective and high-affinity histamine H4 receptor antagonist (Ki: 12.5 nM versus the human H4 receptor). In transfected cells, functionally antagonizes histamine-induced cAMP inhibition ( pA2: 7.9). At the mouse H4R, the Ki=5.3 nM and the pA2=8.3. At the monkey H4R, the Ki=25 nM and the pA2=7.5. The affinity for the rat (Ki=188 nM, pA2 = 7.2) and guinea pig H4R (Ki=306 nM) is moderate, and JNJ 39758979 has little if any affinity for the dog H4R (Ki≥10 μM). The compound is highly selective for H4R, as it exhibits low affinity for the H1, H2, and H3 receptors [1].

JNJ-39758979 (2 mg/kg; i.v.) treatment shows that the Vss, AUC, CL and t1/2 were 19.9 L/kg, 1.4 μM*h, 2.2 L/h, and 2.1 hours, respectively. JNJ-39758979 (10 mg/kg; p.o.) treatment displays that the Cmax, t1/2, and F values are 0.3 μM, 7.5 hours, and 36%, respectively [1].