No head-to-head studies have been conducted, but previous comparisons of drug studies have indicated that they are broadly similarly effective.56 Timapiprant was selected as a dose-ranging study, not powered to look for a difference in exacerbation rate, reported a significant reduction in respiratory infections (12.3% vs 23.1%; p=0.003) and a non-significant reduction in exacerbations (3.8% vs 7.7%; p=0.107) in the pooled dose group29—a signal not seen with any other CRTH2 antagonists. The gene discussed is PTGDR2; the disease is respiratory tract infectious disorder.