Pairwise comparison of levalbuterol versus racemic albuterol in the treatment of moderate-to-severe asthma.

The object of this study is a post hoc pairwise comparison of levalbuterol versus racemic albuterol for asthma in a multicenter, double-blind, randomized, placebo-controlled clinical trial. The participants are patients ≥12 years of age (n = 362) with FEV 1 45-70% of predicted. The patients received nebulized levalbuterol (0.63 or 1.25 mg), racemic albuterol (1.25 or 2.5 mg), or placebo t.i.d. for 4 weeks. The primary endpoints, published in Nelson HS, Bensch G, Pleskow WW, et al. Improved bronchodilation with levalbuterol compared with racemic albuterol in patients with asthma. J Allergy Clin Immunol 102:943-952, 1998, included comparisons of active treatments with placebo and of the combined levalbuterol with the combined racemic albuterol groups for pulmonary function and rescue medication use. After the first dose, levalbuterol 1.25 mg produced a significantly greater increase in the mean peak change in FEV 1 compared with both doses of racemic albuterol (p < 0.03) in all patients and in those with more severe asthma. Levalbuterol 1.25 mg also produced a significantly greater (p < 0.05) mean area under the curve (AUC) of the FEV 1 versus time plot (AUC FEV 1 ) compared with all other treatments after the first dose in all patients and in the subset with mare severe disease, illustrating better overall improvement in FEV 1 . Active treatment groups demonstrated significant improvements compared with the placebo group (p < 0.05), except for A UC FEV 1 in the racemic albuterol 1.25-mg group at week 4. Levalbuterol in the absence of the (S)-isomer provided greater bronchodilation ,than the same quantity of (R)-albuterol delivered as the racemate. These data suggest that (S)-albuterol may compromise the efficacy of (R)-albuterol.