Run in period in all patients with high dose of budesonide (1600 mcg/day) for 3 months. After that, randomization into two groups: 1. The same treatment (1600 mcg/day of budesonide) or combined treatment with lower dose of budesonide (18 mcg/day of formoterol and 800 mcg of budesonide) in a single turbuhaler inhaler during 3 months.