Reducing asthma attacks in children using exhaled nitric oxide (RAACENO) as a biomarker to inform treatment strategy: a multicentre, parallel, randomised, controlled, phase 3 trial.

Background: The benefit of fractional exhaled nitric oxide (FeNO) in guiding asthma treatment is uncertain. We evaluated the efficacy of adding FeNO to symptom-guided treatment in children with asthma versus only symptom-guided treatment.

Methods: RAACENO was a multicentre, parallel, randomised, controlled, phase 3 trial done in 35 secondary care centres and 17 primary care recruitment sites (only seven primary care sites managed to recruit patients) in the UK.