Discovery of CC chemokine receptor-3 (CCR3) antagonists with picomolar potency.
De Lucca GV, Kim UT, Vargo BJ, Duncia JV, Santella JB, Gardner DS, Zheng C, Liauw A, Wang Z, Emmett G, Wacker DA, Welch PK, Covington M, Stowell NC, Wadman EA, Das AM, Davies P, Yeleswaram S, Graden DM, Solomon KA, Newton RC, Trainor GL, Decicco CP, Ko SS.
Starting with our previously described(20) class of CC chemokine receptor-3 (CCR3) antagonist, we improved the potency by replacing the phenyl linker of 1 with a cyclohexyl linker and by replacing the 4-benzylpiperidine with a 3-benzylpiperidine. The resulting compound, 32, is a potent and selective antagonist of CCR3. SAR studies showed that the 3-acetylphenyl urea of 32 could be replaced with heterocyclic ureas or heterocyclic-substituted phenyl ureas and still maintain the potency (inhibition of eotaxin-induced chemotaxis) of this class of compounds in the low-picomolar range (IC(50) = 10-60 pM), representing some of the most potent CCR3 antagonists reported to date. The potency of 32 for mouse CCR3 (chemotaxis IC(50) = 41 nM) and its oral bioavailability in mice (20% F ) were adequate to assess the efficacy in animal models of allergic airway inflammation. Oral administration of 32 reduced eosinophil recruitment into the lungs in a dose-dependent manner in these animal models. On the basis of its overall potency, selectivity, efficacy, and safety profile, the benzenesulfonate salt of 32, designated DPC168, entered phase I clinical trials.