A new selective CRTH2 antagonist named TM30089 is structurally closely related to ramatroban but with less affinity for TP and many other receptors including the related anaphylatoxin C3a and C5a receptors, selected chemokine receptors and the cyclooxygenase isoforms 1 and 2, attenuates airway eosinophilia and mucus cell-hyperplasia in an animal model of asthma [92]. This evidence concerns the gene PTGDR2 and asthma.