Adult and Adolescent Subjects Aged 12 Years and Older

The efficacy of albuterol sulfate HFA was evaluated in two 12-week, randomized, double-blind, placebo-controlled trials in subjects aged 12 years and older with mild to moderate asthma. These trials included a total of 610 subjects (323 males, 287 females). In each trial, subjects received 2 inhalations of albuterol sulfate HFA, CFC 11/12-propelled albuterol, or HFA-134a placebo 4 times daily for 12 weeks’ duration. Subjects taking the HFA-134a placebo inhaler also took albuterol sulfate HFA for asthma symptom relief on an as-needed basis. Some subjects who participated in these clinical trials were using concomitant inhaled steroid therapy. Efficacy was assessed by serial forced expiratory volume in 1 second (FEV 1). In each of these trials, 2 inhalations of albuterol sulfate HFA produced significantly greater improvement in FEV 1over the pretreatment value than placebo. Results from the 2 clinical trials are described below. 

In a 12-week, randomized, double-blind trial, albuterol sulfate HFA (101 subjects) was compared with CFC 11/12-propelled albuterol (99 subjects) and an HFA-134a placebo inhaler (97 subjects) in adolescent and adult subjects aged 12 to 76 years with mild to moderate asthma. Serial FEV 1measurements [shown below as percent change from test-day baseline at Day 1 (n = 297) and at Week 12 (n = 249)] demonstrated that 2 inhalations of albuterol sulfate HFA produced significantly greater improvement in FEV 1over the pretreatment value than placebo. 

FEV 1as Percent Change from Predose in a Large, 12-Week Clinical Trial 

Day 1

Week 12

In the responder population (≥15% increase in FEV 1within 30 minutes postdose) treated with albuterol sulfate HFA, the mean time to onset of a 15% increase in FEV 1over the pretreatment value was 5.4 minutes, and the mean time to peak effect was 56 minutes. The mean duration of effect as measured by a 15% increase in FEV 1over the pretreatment value was approximately 4 hours. In some subjects, duration of effect was as long as 6 hours. 

The second 12-week randomized, double-blind trial was conducted to evaluate the efficacy and safety of switching subjects from CFC 11/12-propelled albuterol to albuterol sulfate HFA. During the 3-week run-in phase of the trial, all subjects received CFC 11/12-propelled albuterol. During the double-blind treatment phase, albuterol sulfate HFA (91 subjects) was compared to CFC 11/12-propelled albuterol (100 subjects) and an HFA-134a placebo inhaler (95 subjects) in adult and adolescent subjects with mild to moderate asthma. Serial FEV 1measurements demonstrated that 2 inhalations of albuterol sulfate HFA produced significantly greater improvement in pulmonary function than placebo. The switching from CFC 11/12-propelled albuterol inhaler to albuterol sulfate HFA did not reveal any clinically significant changes in the efficacy profile. 

In the 2 adult trials, the efficacy results from albuterol sulfate HFA were significantly greater than placebo and were clinically comparable to those achieved with CFC 11/12-propelled albuterol, although small numerical differences in mean FEV 1response and other measures were observed. Physicians should recognize that individual responses to beta-adrenergic agonists administered via different propellants may vary and that equivalent responses in individual patients should not be assumed. 

Pediatric Subjects Aged 4 to 11 Years

The efficacy of albuterol sulfate HFA was evaluated in one 2-week, randomized, double-blind, placebo-controlled trial in 135 pediatric subjects aged 4 to 11 years with mild to moderate asthma. In this trial, subjects received albuterol sulfate HFA, CFC 11/12-propelled albuterol, or HFA-134a placebo. Serial pulmonary function measurements demonstrated that 2 inhalations of albuterol sulfate HFA produced significantly greater improvement in pulmonary function than placebo and that there were no significant differences between the groups treated with albuterol sulfate HFA and CFC 11/12-propelled albuterol. In the responder population treated with albuterol sulfate HFA, the mean time to onset of a 15% increase in peak expiratory flow rate (PEFR) over the pretreatment value was 7.8 minutes, and the mean time to peak effect was approximately 90 minutes. The mean duration of effect as measured by a 15% increase in PEFR over the pretreatment value was greater than 3 hours. In some subjects, duration of effect was as long as 6 hours.