Comparison between the effects of generic and original salmeterol/fluticasone combination (SFC) treatment on airway inflammation in stable asthmatic patients

Abstract

Background: Little is known about the effect of inhaled corticosteroids (ICS)/long-acting β2 agonists (LABA) in combination on inflammatory markers in asthma. In addition, therapeutic equivalence of generic salmeterol/fluticasone combination (SFC) and original SFC is as yet unknown. Objective: To determine the effects of SFC and the effects of generic and original SFC on airway inflammation in patients with mild-to moderate stable asthma. Material and Method: A randomized double-blinded, crossover non-inferiority study was conducted to compare the antiinflammatory effects of generic SFC and original SFC on sputum eosinophils as a primary outcome and fractional exhaled nitric oxide (FENO) as a secondary outcome. Patients: The authors studied 51 mild-to-moderate asthmatic patients who ranged from 18 to 80 years of age and were treated with ICS or ICS/LABA of any dose, and whose asthma was stable without an exacerbation episode for at least 3 months prior to study entry. Results: Both sputum eosinophils percentage and absolute eosinophil counts well correlated with FENO levels at baseline prior to the initiation of study medications. Significant reduction in sputum eosinophil percentage was observed following generic SFC and original SFC treatment. The degree of sputum eosinophil suppression by generic SFC was not inferior to original SFC, and this was not affected by treatments with the sequence of generic SFC first vs. original SFC second or original SFC first vs. generic SFC. In addition, there was no significant difference between treatments in terms of normalized gain in asthma control scores, including the number of patients found to have improved asthma control, irrespective of sequence, as change from baseline. However, this was not the case for the magnitude of FENO reduction that occurred after generic SFC treatment to a significantly larger extent than original SFC treatment. Conclusion: This short-term study demonstrated that there was no significant difference between generic SFC and original SFC in terms of anti-inflammatory activity and the control of asthma symptoms. However, it is completely unknown whether generic SFC could effectively prevent the development of asthma exacerbations on a long-term basis. Therefore, longer-term studies are indicated to evaluate generic SFC's relative efficacy on asthma exacerbations.