TAS 205 is an inhibitor of hematopoietic prostaglandin D synthase (H-PGDS; IC₅₀= 55.8 nM).¹It is selective for H-PGDS over lipocalin-type PGDS (L-PGDS) at 100 µM, as well as over enzyme and receptor panels at 10 µM. TAS 205 inhibits production of prostaglandin D₂induced by A23187 in KU812 human and RBL-2H3 rat basophils with IC₅₀values of 78.3 and 181.3 nM, respectively. It inhibits ovalbumin-induced nasal lavage fluid eosinophil infiltration and late-phase nasal obstruction in an ovalbumin-sensitized guinea pig model of allergic rhinitis when administered at a dose of 30 mg/kg.

1.Aoyagi, H., Kajiwara, D., Tsunekuni, K., et al.Potential synergistic effects of novel hematopoietic prostaglandin D synthase inhibitor TAS-205 and different types of anti-allergic medicine on nasal obstruction in a Guinea pig model of experimental allergic rhinitisEur. J. Pharmacol.875173030(2020)