Patients with cystic fibrosis (CF) suffer from chronic infections of the lower respiratory tract that can be caused by one or multiple bacteria, including Pseudomonas aeruginosa, which has been particularly problematic to eradicate and been implicated as the major cause of morbidity and mortality in CF patients. Aerosol delivery of antibiotics directly to the lung increases the local concentrations of antibiotic at the site of infection resulting in improved antimicrobial effects compared to systemic administration. Bacterial resistance to current aerosol antibiotic treatments indicate a need for improved therapies to treat CF patients with pulmonary infections caused by multi-drug resistant Pseudomonas aeruginosa and other bacteria. High concentrations of MP-376 delivered directly to the lung are projected to have antimicrobial effects on even the most resistant organisms and reduce the emergence of resistant bacteria.

This trial will be a single-blind, placebo-controlled, dose escalating between cohorts, single and multi-dose, multi-center study to evaluate the safety, tolerability and pharmacokinetic profile of levofloxacin administered as MP-376 once, then twice daily for 14 days by the aerosol route to CF patients.

Study acquired from Horizon in 2024.

Inclusion Criteria:

• > 16 years of age
• Confirmed Diagnosis of Cystic Fibrosis
• Positive sputum culture for P. aeruginosa within the past 6 months
• Patients are able to elicit an FEV1 >/= 40% of predicted value at screening
• Clinically stable with no evidence of acute respiratory or lower respiratory infections within 28 days prior to dosing
• Able to reproducibly perform spirometry measurements and be able to repeatedly produce sputum over several hours

Exclusion Criteria:

• Use of any nebulized or systemic antibiotics within 4 weeks of starting study
• History of hypersensitivity to fluoroquinolones or intolerance with aerosol medication
• Uncontrolled diabetes or abnormal renal function
• Tobacco use (smoking) in the last 30 days