- Clinical diagnosis of asthma for a minimum of 12 months prior to screening confirmed by a chest physician according to international guidelines (GINA). The evidence of asthma must be confirmed through a documented (in the last three years) positive response to the reversibility test, defined as ΔFEV1 ≥ 12% and ≥ 200 mL over baseline, within 30 minutes after administration of 400 μg of salbutamol pMDI or through a documented (in the last three years) positive response to methacholine challenge test (PC20 < 8 mg/mL or PD20 < 1 mg).