Clinical equivalence of salmeterol/fluticasone propionate in combination (50/100 μg twice daily) when administered via a chlorofluorocarbon-free metered dose inhaler or dry powder inhaler to patients with mild-to-moderate asthma

Abstract

This multi-centre, randomized, double-blind, double-dummy, parallel-group study was designed to investigate the hypothesis of equivalent efficacy and comparable safety of two inhaled presentations of salmeterol/fluticasone propionate combination product (SALM/FP) 50/100 μg administered twice daily to patients with mild-to-moderate asthma for 12 weeks. The delivery systems were a 25/50 μg strength hydrofluoroalkane (HFA) metered-dose inhaler (MDI) and a DiskusTMinhaler (50/100 μg strength). A third group received FP 100 μg twice daily via a chlorofluorocarbon MDI (50 μg strength). A total of 497 patients aged 11–79 years with reversible airways obstruction who were symptomatic on inhaled corticosteroid (ICS) therapy and had room for improvement in lung function were randomized to treatment in a double-blind, parallel-group design (SALM/FP MDI: n=165; SALM/FP DiskusTM: n=167; FP MDI:n =165) for 12 weeks. A total of 383 patients completed the study according to the protocol.According to the primary efficacy variable, increase in mean morning PEF over weeks 1–12, the two inhaled presentations of SALM/FP were clinically equivalent (adjusted mean increases 43 and 46 l min−1; treatment difference 3 l min−1; 95% confidence interval: −6 to 11 l min−1). Equivalence was also demonstrated by all secondary efficacy measures. The SALM/FP MDI was significantly superior to the FP MDI for increase in mean morning PEF (treatment difference 19 l min−1;P<0·001) and for all secondary measures except FEV1and symptom-free nights. There was no significant difference between the groups with respect to adverse events and serum cortisol levels.These results demonstrate that the SALM/FP 25/50 μg HFA MDI (two inhalations twice daily) is clinically equivalent to the SALM/FP 50/100 μg DiskusTM(one inhalation twice daily). Patients switching to SALM/FP from other MDI-based asthma treatments may now do so without a change of delivery device.