Study objective: To compare the long-term efficacy and safety of albuterol administration using a Spiros Inhalation System (Dura Pharmaceuticals; San Diego, CA) dry powder inhaler (DPI) and albuterol (Ventolin; Glaxo Wellcome; Research Triangle Park, NC) administration using a metered-dose inhaler (MDI) in patients with asthma.
Materials and methods: This was a phase III, 12-week, randomized, double-blind, double-dummy, placebo-controlled, parallel-group, multicenter study of 283 adolescent and adult patients with mild to moderate asthma. The patients were randomized into one of three treatment groups: the Spiros group, who were given 108 microg/actuation of albuterol sulfate equivalent to 90 microg of albuterol base; the MDI group, who were given 90 microg/actuation of albuterol; and the placebo group.
Results: Over the length of the study, the Spiros and MDI groups were comparable in all FEV1 parameters. Both active treatment groups were superior to the placebo group for each FEV1 parameter at all visits. With the exception of differences at treatment week 0 for the maximum percent change in the FEV1, the duration of effect, and the area under the curve at baseline, there were no statistically significant differences between the Spiros and MDI groups for any FEV1 parameters. Using a repeated-measures analysis, the FEV1 parameters at week 0 for the Spiros group were not statistically significantly different from the parameters at weeks 4, 8, and 12. The same analysis effect at week 0 for the MDI group was greater for maximum percent change in the FEV1 from baseline (weeks 4, 8, and 12) and duration of effect. Adverse events and changes in clinical laboratory values, vital signs, ECG results, and physical examinations were reported with similar incidence in each of the three treatment groups.
Conclusion: Both active treatments were superior to the placebo treatment. The Spiros DPI was well tolerated and was as effective as the albuterol MDI in treating patients with moderate asthma.