Effect of addition of inhaled salmeterol to the treatment of moderate-to-severe asthmatics uncontrolled on high-dose inhaled steroids. European Respiratory Study Group.
The aim of this study was to assess the efficacy and safety of inhaled salmeterol 100 micrograms b.d. (SM) versus inhaled salbutamol 400 micrograms q.d.s. (SB), both via the Diskhaler, when added to concurrent treatment, in asthmatic patients who were not controlled on high doses of inhaled steroids (> or = 1,500 micrograms beclomethasone dipropionate (BDP) or equivalent daily). This was a multicentre, parallel group, double-blind study in which 190 patients with a forced expiratory volume in one second (FEV1) or peak expiratory flow rate (PEFR) of 30-75% predicted and 15% reversibility to inhaled bronchodilator were randomized to treatment for 6 weeks. In the SM group, morning PEFR increased from 281 to 315 L-min-1 during treatment and in the SB group from 311 to 315 L.min-1 (p < 0.001). The SM group showed significantly better reduction in diurnal variation, from 39 to 22 L.min-1 during treatment, than the SB group (34 to 37 L.min-1) (p < 0.001). There was a significantly greater improvement in FEV1 in the SM group (from 1.63 to 1.85 L) than in the SB group (from 1.79 to 1.84 L). The SM group had significantly more symptom-free nights than the SB group (p < 0.001), and also more "rescue-free" nights (p = 0.04). The adverse event profile was similar in both groups. This study indicates that in asthmatic patients, not controlled on high-dose inhaled steroids, inhaled salmeterol 100 micrograms b.d. significantly improves lung function and reduces asthma symptoms.