Salmeterol/Fluticasone 50/500 mcg Inhalation Powder Via Capsair vs Seretide Diskus 500 mcg Inhalation Powder in Patients With COPD

The aim of the current study is to compare the efficacy and safety of Salmeterol/Fluticasone 50/500 mcg Inhalation Powder treatment administered via Capsair twice daily and original product Seretide Diskus 500 mcg Inhalation Powder treatment twice daily in patients with moderate-severe COPD. Patients who met all the inclusion criteria will enter a 1-week run-in period with the length determine by the specific medication, during which their usual treatment will be stopped and they will receive salbutamol as required. Following run-in period, patients will be randomly assigned to receive Salmeterol/Fluticasone 50/500 mcg as dry powder capsule for inhalation by Capsair or Salmeterol/Fluticasone 50/500 mcg as dry powder for inhalation by Diskus twice daily for 8-weeks treatment period. Patients will be evaluated at 6 consecutive visits: baseline (enrollment), screening, treatment (treatment initiation, after 4 and 8 weeks of treatment) and after treatment (will carry out by telephone two weeks following the last dose of study medication). Spirometric measurements will be performed at 12 different time points at pre-treatment and post-treatment (5. min, 15. min, 30. min, 1. hr, 2. hr, 3.hr, 4.hr, 6.hr, 8.hr, 10.hr and 12.hr) during the treatment visits of 11-weeks study period. Safety will be assessed through vital signs, adverse events, serious adverse events and all cause mortality.