Clinical equivalence of a salmeterol/fluticasone propionate combination product (50/500μg) delivered via a chlorofluorocarbon-free metered-dose inhaler with the Diskus™ in patients with moderate to severe asthma

Abstract

Objective To demonstrate equivalent efficacy and comparable tolerability of two inhaled combined formulations of salmeterol/fluticasone propionate (SALM/FP) 50/500μg twice daily in asthma patients.

Design and Setting Multicentre, double-blind, parallel-group study.

Patients Patients aged 12 to 82 years with moderate to severe asthma who were symptomatic on existing inhaled corticosteroid therapy.

Methods 176 patients were randomised to SALM/FP 50/500μg twice daily via a novel hydrofluoroalkane (HEA) metered-dose inhaler (MDI; 25/250μg per actuation), and 161 received the same dosage of SALM/FP via a dry powder Diskus™ inhaler (50/500μg) for 12 weeks. A third group of patients (n = 172) received the same dosage of steroid, FP 500μg twice daily, alone via a chlorofluorocarbon (CFC) MDI (250μg per actuation). The primary efficacy parameter was change in morning peak expiratory flow (PEF) over weeks 1 to 12.

Results The SALM/FP MDI was clinically equivalent to the SALM/FP Diskus™ for the mean change in morning PEF over weeks 1 to 12 [adjusted mean increases 50 and 48 L/min, respectively; treatment difference −2 L/min; 95% confidence interval (CI):−11 to 7 L/min]. The SALM/FPMDI produced significantly greater improvements in morning PEF than the FPMDI (difference: −23 L/min; 95% CI: −32 to −14), with superiority for all secondary efficacy measures. All three treatments were well tolerated, with similar profiles and incidences of adverse events.

Conclusions At a dosage of 50/500μg twice daily, the SALM/FP 25/250μg HFA MDI (two actuations twice daily) is clinically equivalent to the SALM/FP 50/500μg Diskus™ (one actuation twice daily). The availability of two formulations offers patients a choice of delivery systems when switching to combination therapy with SALM/FP.