There were no differences between treatment groups in clinical exacerbation severity including cumulative lower respiratory symptom score day 0–14 (difference 3.0 (95% CI −29.0 to 17.0), p=0.78), virus load, antiviral immune responses, or RV-A16-induced airway inflammation other than in the bronchial biopsies, where CRTH2 staining was increased during RV-A16 infection in the placebo-treated but not the timapiprant-treated group. This evidence concerns the gene PTGDR2 and inflammatory response.