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

Objective: To demonstrate equivalent efficacy and comparable tolerability o f two inhaled combined formulations of salmeterol/fluticasone propionate (S ALM/FP) 50/500 mug 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 w ere symptomatic on existing inhaled corticosteroid therapy. Methods: 176 patients were randomised to SALM/FP 50/500 mug twice daily via a novel hydrofluoroalkane (HFA) metered-dose inhaler (MDI; 25/250 mug per actuation), and 161 received the same dosage of SALM/FP via a dry powder Di skusTM inhaler (50/500 mug) for 12 weeks. A third group of patients (n = 17 2) received the same dosage of steroid, FP 500 mug twice daily, alone via a chlorofluorocarbon (CFC) MDI (250 mug 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 DiskusTM for the mean change in morning PEF over weeks 1 to 12 [adjusted mean increa ses 50 and 48 L/min, respectively; treatment difference -2 L/min; 95% confi dence interval (CI): -11 to 7 L/min]. The SALM/FP MDI produced significantl y greater improvements in morning PEF than the FP MDI (difference: -23 L/mi n; 95% CI: -32 to -14), with superiority for all secondary efficacy measure s. All three treatments were well tolerated, with similar profiles and inci dences of adverse events. Conclusions: At a dosage of 50/500 mug twice daily, the SALM/FP 25/250 mug HFA MDI (two actuations twice daily) is clinically equivalent to the SALM/F P 50/500 mug DiskusTM (one actuation twice daily). The availability of two formulations offers patients a choice of delivery systems when switching to combination therapy with SALM/FP.