Study objective: To compare the dose response, efficacy, and safety of inhaled triamcinolone acetonide (TAA) with a hydrofluoroalkane (HFA) propellant (75 microg/puff), TAA with a chlorofluorocarbon propellant (dichlorodifluoromethane [P-12]; 75 microg/puff), and placebo in adult patients with persistent asthma.
Design: Multicenter, randomized, double-blind, placebo-controlled, parallel-group study of 514 adult patients with persistent asthma.
Interventions and measurements: Patients received 8 weeks of treatment with 150, 300, or 600 microg/d of TAA HFA, the same doses of TAA P-12, or placebo following a 5- to 21-day baseline period. Efficacy was assessed by spirometry, and by daily recordings of albuterol use, peak expiratory flow (PEF), asthma symptom ratings, and nighttime awakenings throughout the study.
Results: Linear trend analysis showed that both formulations of TAA at all doses produced statistically significant improvements compared with placebo in spirometry, asthma symptom scores, albuterol use, and PEF. Significant improvement was seen as early as 24 h for morning PEF and as early as 1 week for FEV(1) (TAA HFA, 600 microg/d; TAA P-12, 300 and 600 microg/d) and albuterol use (all doses of both formulations). The P-12 and HFA formulations had comparable efficacy. A dose response showing greater improvement with higher doses was evident for the majority of parameters for both formulations. The incidences of adverse events were similar across all treatment groups with no dose-related trends.
Conclusion: HFA and P-12 formulations of TAA inhalation aerosol were therapeutically equivalent and showed comparable safety and dose-related efficacy in the treatment of patients with persistent asthma.