Phenotyping patients with chronic cough: Evaluating the ability to predict the response to anti-inflammatory therapy.

Background: Whether the fraction of exhaled nitric oxide (FeNO) measurement can predict the response to anti-inflammatory treatment in chronic cough is unknown.

Objective: To explore whether the effectiveness of treatment with 10 mg of montelukast or 20 mg of prednisolone in patients with chronic cough is predicted by FeNO level.

Methods: In this randomized, open-label, controlled pilot study conducted in the Clinical Trial Unit in Castle Hospital in the United Kingdom, 50 nonsmoking patients with a cough that lasted more than 8 weeks were sequentially enrolled in the study. Thirty patients with high FeNO levels (≥30 ppb) were randomized in a 1:1 ratio to receive 10 mg of montelukast or 20 mg of prednisolone for 2 weeks followed by 10 mg of montelukast for 2 weeks. Twenty patients with a low FeNO level (≤20 ppb) received 10 mg of montelukast. The primary objective was to determine the effectiveness of treatment on 24-hour cough counts.

Results: The 24-hour cough counts decreased in both groups by approximately 50% (P < .005), indicating that FeNO did not predict treatment response. However, it was a good marker for eosinophilic inflammation with a high degree of correlation with blood and sputum eosinophilia (P < .001).

Conclusion: These results suggest that prior investigation may not predict response to anti-inflammatory treatment, which may be consequent on localized leukotriene-mediated inflammation.

Trial Registration: ClinicalTrials.gov Identifier: NCT02479074.