A Study to Evaluate the Onset of Relief From Methacholine-induced Bronchoconstriction With CHF1535 NEXThaler in Asthmatic Patients.

Inclusion Criteria: * Informed consent form obtained * Minimum required Peak Inspiratory Flow (PIF) to activate NEXThaler * Pre-bronchodilator FEV1 of at least 65% * Positive response to methacholine challenge test * Previous treatment with low-medium doses of Inhaled Corticosteroids (ICS) or ICS/Long-acting beta2-agonist (LABA) as per Global Initiative for Asthma (GINA) 2016 guidelines * For females: non-pregnant, non-lactacting and using highly effective contraceptive methods. Exclusion Criteria: * Clinically relevant and uncontrolled concomitant diseases * Abnormal clinically relevant ECG * Presence of aortic aneurism * Uncontrolled hypertension * Intake of non-permitted concomitant medications * Participation in another clinical trials in the previous 8 weeks * Seasonal variation in asthma * Recent occurrence of asthma exacerbations * Hypersensitivity to any product used in the trial, including excipients * Heavy caffeine drinkers * History of alcohol/drug abuse * Smokers