An evaluation of levalbuterol HFA in the prevention of exercise-induced bronchospasm

Abstract

Background: Exercise-induced bronchospasm (EIB) affects up to 90% of all patients with asthma. Objective. This study evaluated the ability of levalbuterol hydrofluoroalkane (HFA) 90 mug (two actuations of 45 microg) administered via metered dose inhaler (MDI) to protect against EIB in mild-to-moderate asthmatics.

Methods: This was a randomized, double-blind, placebo-controlled, two-way cross-over study. Patients with asthma (n = 15) were > or =18 years, had a > or =6-month history of EIB, > or = 70% baseline predicted forced expiratory volume in 1 second (FEV1), and a 20% to 50% decrease in FEV(1) after treadmill exercise challenge using single-blind placebo MDI. Levalbuterol or placebo was self-administered 30 minutes before exercise. Treatment sequences were separated by a 3-to 7-day washout period. Spirometry was performed predose, 20 minutes postdose/pre-exercise, and 5, 10, 15, 30, and 60 minutes post-exercise. The primary endpoint was the maximum percent decrease in FEV1 from baseline (postdose/pre-exercise). The percentage of protected (< or = 20% decrease in post-exercise FEV1) patients was also assessed.

Results: Levalbuterol had significantly smaller maximum percent post-exercise decrease in FEV1 compared with placebo (LS mean +/- SE; -4.8% +/- 2.8% versus -22.5% +/- 2.8%, respectively). For levalbuterol, 14/15 (93.3%) patients had < 20% decrease in post-exercise FEV1 compared with 8/15 (53.3%) for placebo (p = 0.0143). Treatment was well tolerated.

Conclusion: Levalbuterol HFA MDI (90 microg) administered 30 minutes before exercise was significantly more effective than placebo in protecting against EIB after a single exercise challenge and was well tolerated.

Clinical implications: Levalbuterol HFA MDI when administered before exercise was effective in protecting adults with asthma from EIB.

Figure 1

(A) Maximum percent decrease in FEV₁ for each patient from postdose/pre-challenge after treatment with placebo (DB-placebo) or levalbuterol (DB-levalbuterol) during the double-blind period for each patient. Patient numbers (see Table 2) are indicated and the solid grey lines are to aid following individual patient values. LS-mean (Least square mean) is the adjusted means for the effects in the model (see methods). (B) Percent of patients protected at 10%, 15%, and 20% is indicated.

Figure 2

The mean FEV₁ predose, postdose/pre-exercise challenge, and at each time point post-exercise after treatment with levalbuterol or placebo. The standard deviation for each point is indicated.