Study to Assess the Efficacy of a Single PBF-680 Oral Administration to Attenuate Adenosine 5'-Monophosphate Challenge-induced Airway Hyperresponsiveness in Mild-to-moderate Asthmatics

A Single-centre, Randomised, Double-blind, Placebo-controlled, 3-way Multiple Dose, Cross-over, "Proof-of-concept" Study to Assess the Efficacy of a Single PBF-680 Oral Administration to Attenuate Adenosine 5'-Monophosphate (AMP) Challenge-induced Airway Hyperresponsiveness in Mild-to-moderate Asthmatics