Use of ibuprofen to assess inflammatory biomarkers in induced sputum: Implications for clinical trials in cystic fibrosis
High-dose ibuprofen (HDI) is a clinically beneficial anti-inflammatory regimen that may be a useful reagent to study induced sputum inflammatory marker changes over short study periods appropriate for early-phase CF clinical trials. We conducted a 28-day, open-label, randomized, controlled trial among 72 clinically stable CF subjects (FEV1≥40% predicted) randomized to HDI or routine care that assessed IL-6, IL-8, TNF-α, IL-1-β, free neutrophil elastase, and white cell counts with differentials change from baseline in induced sputum. IL-6 was the only biomarker with significant within-group change: 0.13 log10 pg/mL mean reduction among ibuprofen-treated subjects (p=0.04); and no change in the control group. IL-6 change between groups was statistically significant (p=0.024). No other inflammatory biomarker differences were observed between groups after 28 days. Although we studied only one agent, HDI, these results suggest that one month may be inadequate to assess anti-inflammatory candidates using markers from induced sputum.