Objectives: This multicenter, double-blind, placebo-controlled study evaluated the dose response to 6 weeks of triamcinolone acetonide inhalation aerosol (TAA, 100 µg per puff) in patients with moderately severe asthma.
Study design: A total of 285 patients were randomly assigned to treatment with 1, 2, 4, or 8 puffs TAA (total daily doses of 200, 400, 800, and 1,600 µg, respectively), administered twice daily, or matching placebos. Efficacy was assessed by changes in FEV1, asthma symptom scores, albuterol use, and peak flow rates.
Results: Linear trend analyses showed a dose response for all efficacy variables across the dose range of 200 to 1,600 µg daily. Therapeutic activity was evident at a dose of 200 µg daily for all variables, with significant clinical efficacy (p<0.05) demonstrated for all doses except for reduction in inhaled albuterol use which achieved statistical significance at 400 µg/d. Daily doses of 400 µg and higher showed response plateaus at 3 weeks of treatment that were maintained for the remainder of the trial. The incidence of adverse events was similar in all treatment groups, although more patients treated with TAA reported pharyngitis in a dose-related manner.
Conclusions: Our findings suggest that most patients with chronic, moderately severe asthma can be treated adequately with doses of TAA between 200 µg (1 puff bid) and 800 µg (4 puffs bid) daily. At this dose range, clinically significant improvements are evident in symptoms, pulmonary function, and rescue medication use.