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

This is a single-center, double-blind, randomized trial utilizing a three-period, balanced block design, with each period comprising a unique study product administration. The treatments studied are PBF-680 5 mg, PBF-680 20 mg and placebo, as an orally administered capsule. The study includes a screening visit, a selection visit, three visits for the randomized treatment sequence, and an end-of-study follow-up visit, spanning through a 65-day maximum study duration. The study will be conducted on 18 male or female adults aged ³18 years, with a diagnosis of stable, mild to moderate asthma as per GINA guidelines, with no smoking or less than a 5 packs-years smoking history history, responsive to AMP airway challenge as determined in the selection visit. The primary efficacy variable will be the PC20 yielded from AMP airway challenge testing at the three treatment visits. FeNO, sampled at three time points at each treatment period visit, will be a exploratory variable. Safety assessment will include monitoring of adverse events, physical examination, vital signs, EKGs, spirometry, serum and urine pregnancy tests, and laboratory determinations. Blood sampling at a time-point series will provide pharmacokinetics data. The primary variable of the study is PC20, mg×mL-1. The PC 20 distributions will be analyzed by treatment using ANOVA for repeated measurements, followed by post hoc pairwise comparisons as appropriate. Other analyses will comprise FeNO, pharmacokinetics, data sets generated from baseline characteristics and safety assessments, and discretionary expiratory analyses to evaluate the influence of baseline and clinical covariates on the primary variable.