CS-003 Free base (CS-003), a triple tachykinin receptor antagonist, shows high affinities for human (Neurokinin) NK1, NK2 and NK3 receptors with Ki values of 2.3 nM, 0.54 nM and 0.74 nM, respectively. CS-003 Free base (CS-003) has therapeutic efficacy on respiratory diseases associated with neurokinins. NK1|2.3 nM (Ki)|NK2|0.54 nM (Ki)|NK3|0.74 nM (Ki) CS-003 (0.01-10 μM; 24 hours) inhibits NK1, NK2 or NK3 induced inositol phosphate formation in a concentration-dependent manner with pA2 values of 8.7, 9.4 and 9.5 μM, respectively. CS-003 (intravenous injection; 0.01-3.0 mg/kg; 5 min before neurokinin A/B/C injection) inhibits substance P-induced tracheal vascular hyperpermeability, neurokinin A- and neurokinin B-induced bronchoconstriction with ID50 values of 0.13, 0.040 and 0.063 mg/kg, respectively.