During 2012, a number of respiratory drug projects and individual agents were discontinued, for a variety of reasons, including toxicity, lack of efficacy, commercial re-evaluation and change in corporate focus. These included three antagonists of chemoattractant receptor-homologous molecule expressed on Th2 cells (CRTh2), which had been evaluated in allergic respiratory disease and (in one case) chronic obstructive pulmonary disease (COPD), and other agents intended for the treatment of asthma, COPD, pulmonary hypertension and lung fibrosis. These have been reviewed against the background of a general reduction in respiratory research by the pharmaceutical industry.