Background: Adjustable maintenance dosing with budesonide/formoterol in a single inhaler (Symbicort, AstraZeneca, Lund, Sweden) may provide a convenient means of maintaining asthma control with the minimum effective medication level.
Objectives: To compare adjustable and fixed maintenance dosing regimens of budesonide/formoterol in asthma.
Methods: This was an open-label, randomized, parallel-group, multicentre, Canadian study of asthma patients (aged 12 years or older, postbronchodilator forced expiratory volume in 1 s 70% or greater of predicted normal). Following a one-month run-in on budesonide/formoterol (100/6 µg or 200/6 µg metered doses, two inhalations twice daily), 995 patients were randomly assigned either to continue on this fixed dosing regimen or to receive budesonide/formoterol adjustable dosing (step down to one inhalation twice daily if symptoms were controlled or temporarily step up to four inhalations twice daily for seven or 14 days if asthma worsened). The primary efficacy variable was the occurrence of exacerbations (requiring oral or inhaled corticosteroids, emergency department treatment, serious adverse events or added maintenance therapy because of asthma).
Results: With adjustable dosing, significantly fewer patients experienced exacerbations compared with fixed dosing (4.0% versus 8.9%, P=0.002; number needed to treat=21 [95% CI 13 to 59]). Patients required 36% fewer overall doses of budesonide/formoterol (2.5 versus 3.9 inhalations/day, P<0.001), and total costs per patient were lower (difference over five months -141 Canadian dollars [95% CI -162 Canadian dollars to -116 Canadian dollars]). Asthma symptom severity (modified National Heart, Lung, and Blood Institute stage) was maintained or improved in 97% or greater of patients in both groups (pre-run-in to end of treatment). Both treatments were well tolerated.
Conclusions: Budesonide/formoterol adjustable maintenance dosing provided more effective asthma control than fixed dosing, with a lower overall drug dose and reduced total cost.