Although, major breakthroughs in the clinical usefulness of CRTH2 antagonists are still to be anticipated, recent studies in allergic asthma are showing promising results: Fevipriprant improved lung function in a subgroup of patients suffering from severe air flow limitation [31] and timapriprant (OC000459) beneficially altered asthma control as well as lung function in atopic eosinophilic asthmatics [32]. Here, PTGDR2 is linked to asthma.