Background: Current UK and international guidelines on asthma management recommend that, in pediatric patients still symptomatic on treatment with high-dose inhaled corticosteroids, consideration should be given to the introduction of regular twice daily long-acting beta 2-agonists.

Objective: The purpose of this study was to assess the efficacy and safety of inhaled salmeterol xinafoate 50 micrograms bid via the Diskhaler when added to the existing treatment of children with moderate to severe asthma.

Methods: A 12-week multicenter, double-blind, placebo-controlled, parallel group study was conducted at 78 hospital centers throughout the United Kingdom, involving 210 asthmatic children aged between 4 and 16 years of age. Morning peak expiratory flow (PEF), evening PEF, night-time and daytime symptoms and relief medication usage were recorded daily by the patient or parent over a 12-week treatment period.

Results: Compared with placebo, the addition of salmeterol xinafoate to existing high dose inhaled corticosteroid treatment significantly improved mean morning PEF expressed as percent predicted (PEF-PP) during the first 4 weeks of treatment (median increase 6.5 percentage points P < .001). This effect persisted throughout the 12-week treatment period (P < .05). Both groups demonstrated an overall improvement in mean morning PEF-PP, 7.5 percentage points for salmeterol xinafoate and 4 percentage points for placebo. The mean evening PEF-PP followed a similar although less pronounced trend which was significant only during the first 4 weeks of treatment (P = .014). Daytime relief medication and recorded symptoms were reduced significantly in both groups. There was a greater improvement in the number of symptom-free days during the first 4 weeks (P < .01) and the last 4 weeks (P < .05) of treatment for salmeterol xinafoate. The overall incidence and nature of minor adverse events was similar in both groups.

Conclusions: This study demonstrates that the addition of salmeterol xinafoate to inhaled corticosteroid therapy in symptomatic asthmatic children significantly improves morning PEF-PP, and reduces their symptoms and use of relief medication.