Safety and Tolerability of Single Ascending Doses of PUL-042 Inhalation Solution in Healthy Subjects

The study will assess the safety, tolerability, pharmacokinetics and pharmacodynamics of single ascending doses of PUL-042 inhalation solutions in healthy subjects. Subjects will be enter a screening period of up to 14 days to determine eligibility. Subjects will be admitted to the Phase 1 unit the day prior to dosing and remain in the unit until 24 hours post-dose. Subjects will be seen in the clinic at 3 and 7 days post-dose A modified 3+3 design will be used to determine the maximum tolerated dose (MTD) based on the occurrence of dose-limiting toxicities (DLTs) defined by Common Terminology Criteria for Adverse Events (CTCAE) v4. Additional specific DLTs will be defined as: 1) Hypoxia, defined as a non-artifactual drop in pulse oximetry to \< 90% on room air, 2) A decrease in forced expiratory volume in one second (FEV1) of 12% or greater compared to the last observation prior to dosing, 3) Any evidence of bronchospasm or wheezing requiring medical intervention. Doses will be doubled until the maximum tolerated dose (MTD- defined as the largest dose with 0/6 or 1/6 DLTs) is reached.