RS-1748, a Novel CC Chemokine Receptor 4 Antagonist, Inhibits Ovalbumin-Induced Airway Inflammation in Guinea Pigs

CC chemokine receptor 4 (CCR4) is generally recognized as a preferential marker for T helper 2 cells, and we have previously reported morpholine-derivative CCR4 antagonists, RS-1154 and RS-1269. Here, we investigate the pharmacological profiles of a novel pyrimidine-derivative CCR4 antagonist, 2-{4-[2-(diethylamino)ethoxy]phenyl}-N-(2,4-difluorobenzyl)-5-fluoropyrimidin-4-amine (RS-1748), which showed potency to inhibit the bindings of [125I]CCL17 and [35S]GTPγS to human CCR4-expressing Chinese hamster ovary (CHO) cells with IC50 values of 59.9 nM and 18.4 nM, respectively. Furthermore, RS-1748 inhibited ovalbumin-induced airway inflammation in guinea pigs at a dose of 10 mg/kg. These results indicate that RS-1748 would be a promising lead compound for developing a therapeutic agent against asthma.