In a randomized, double-blind, placebo-controlled, cross-over study, 20 adults with mild-to-moderate asthma received single doses of XopenexInhalation Solution (0.31, 0.63, and 1.25 mg) and racemic albuterol sulfate inhalation solution (2.5 mg). All doses of active treatment produced a significantly greater degree of bronchodilation (as measured by percent change from pre-dose mean FEV₁) than placebo, and there were no significant differences between any of the active treatment arms. The bronchodilator responses to 1.25 mg of Xopenex Inhalation Solution and 2.5 mg of racemicalbuterol sulfate inhalation solution were clinically comparable over the 6-hour evaluation period, except for a slightly longer duration of action ( > 15%increase in FEV₁ from baseline) after administration of 1.25 mg of Xopenex Inhalation Solution. Systemic beta-adrenergic adverse effects were observedwith all active doses and were generally dose-related for (R)-albuterol. Xopenex Inhalation Solution at a dose of 1.25 mg produced a slightly higher rateof systemic beta-adrenergic adverse effects than the 2.5 mg dose of racemic albuterol sulfate inhalation solution.

In a randomized, double-blind, placebo-controlled, cross-over study, 12 adults with mild-to-moderate asthma were challenged with inhaled methacholine chloride 20 and 180 minutes following administration of a single dose of 2.5 mg of racemic albuterol sulfate, 1.25 mg of Xopenex, 1.25 mg of(S)-albuterol, or placebo using a PARI LC Jet™ nebulizer. Racemic albuterol sulfate, Xopenex, and (S)-albuterol had a protective effect against methacholine-induced bronchoconstriction 20 minutes after administration, although the effect of (S)-albuterol was minimal. At 180 minutes after administration, the bronchoprotective effect of 1.25 mg of Xopenex was comparable to that of 2.5 mg of racemic albuterol sulfate. At 180 minutes after administration, 1.25 mg of (S)-albuterol had no bronchoprotective effect.

In a clinical study in adults with mild-to-moderate asthma, comparable efficacy (as measured by change from baseline FEV₁) and safety (as measuredby heart rate, blood pressure, ECG, serum potassium, and tremor) were demonstrated after a cumulative dose of 5 mg of Xopenex Inhalation Solution(four consecutive doses of 1.25 mg administered every 30 minutes) and 10 mg of racemic albuterol sulfate inhalation solution (four consecutive dosesof 2.5 mg administered every 30 minutes).

Clinical Trials (Adults and Adolescents ≥ 12 years old)

The safety and efficacy of Xopenex Inhalation Solution were evaluated in a 4-week, multicenter, randomized, double-blind, placebo-controlled, parallel-group study in 362 adult and adolescent patients 12 years of age and older, with mild-to-moderate asthma (mean baseline FEV₁ 60% of predicted).Approximately half of the patients were also receiving inhaled corticosteroids. Patients were randomized to receive Xopenex 0.63 mg, Xopenex 1.25 mg,racemic albuterol sulfate 1.25 mg, racemic albuterol sulfate 2.5 mg, or placebo three times a day administered via a PARI LC Plus™ nebulizer and aDura-Neb® portable compressor. Racemic albuterol delivered by a chlorofluorocarbon (CFC) metered dose inhaler (MDI) was used on an as-neededbasis as the rescue medication.

Efficacy, as measured by the mean percent change from baseline FEV₁, was demonstrated for all active treatment regimens compared with placebo onday 1 and day 29. On both day 1 (see Figure 1) and day 29 (see Figure 2), 1.25 mg of Xopenex demonstrated the largest mean percent change frombaseline FEV₁ compared with the other active treatments. A dose of 0.63 mg of Xopenex and 2.5 mg of racemic albuterol sulfate produced a clinicallycomparable mean percent change from baseline FEV₁ on both day 1 and day 29.

Figure 1: Mean Percent Change from Baseline FEV₁ on Day 1, Adults and Adolescents ≥ 12 years old

Figure 2: Mean Percent Change from Baseline FEV₁ on Day 29, Adults and Adolescents ≥ 12 years old

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