Gemilukast (ONO-6950) is an orally active and potent dual inhibitor of cysteinyl leukotriene 1 and 2 receptors (CysLT1 and CysLT2), inhibits LTC 4-induced bronchoconstriction, and is inhibitory to human CysLT1 and CysLT2, and may be used in the treatment of asthma.

Gemilukast is a potent dual antagonist for cysteinyl leukotriene 1 and 2 receptors (CysLT1 and CysLT2), and it is orally active. It exhibits IC50 values of 1.7 nM and 25 nM for human CysLT1 and CysLT2, respectively[2]. In comparison, both Gemilukast (ONO-6950) and montelukast inhibit the human CysLT1 receptor-mediated calcium response, with IC50 values of 1.7 nM and 0.46 nM, respectively[1].

Orally administered Gemilukast, at doses ranging from 0.03 to 10 mg/kg, demonstrates a dose-dependent attenuation of LTC4-induced bronchoconstriction, reaching almost complete inhibition at 3 mg/kg. Notably, Gemilukast's inhibitory effect on LTC4-induced bronchoconstriction is significantly stronger than that observed with montelukast at doses equal to or greater than 1 mg/kg.Furthermore, Gemilukast (at doses from 0.03 to 1 mg/kg, p.o.) dose-dependently attenuates LTD4-induced airway vascular hyperpermeability, achieving complete inhibition at 0.3 mg/kg. In the context of OVA-induced bronchoconstriction, Gemilukast at doses ranging from 0.1 to 3 mg/kg, p.o., exhibits a dose-dependent inhibitory effect. Particularly, the inhibitory effect of Gemilukast at 3 mg/kg surpasses that of montelukast alone and is comparable to the combination therapy involving montelukast and BayCysLT2RA[2].