OC-459 is a highly potent and selective CRTH2 antagonist which is active on both the recombinant and native human receptor. The Atopix lead compound OC-459 is effective in improving lung function and symptoms in patients with atopic eosinophilic asthma. This group represents 40-50% of all asthmatics and the magnitude of improvement in the responder population is equivalent to high dose inhaled corticosteroids. OC-459 has also been shown to reduce both nasal and eye symptoms in allergic subjects exposed to grass pollen. Of particular interest is the ability of OC-459 to reduce the rate of respiratory infections, an effect related to reduction in Th2 immunity which has a damaging effect on host defence. OC-459 has also demonstrated an excellent safety profile in around 800 subjects exposed drug and no safety issues have been highlighted in long term toxicology. OC-459 is in Phase 2 clinical trial in patients with moderate to severe atopic dermatitis.