A major factor in the respiratory health of cystic fibrosis (CF) subjects is acquisition of chronic Pseudomonas aeruginosa infections. The infection rate with P. aeruginosa increases with age and by age 18 years, 80% of CF subjects in the U.S. are infected. Liposomal Amikacin for Inhalation (Arikace™) is a sterile aqueous liposomal suspension consisting of amikacin sulfate encapsulated in liposomes. This formulation of amikacin maximizes the achievable dose and delivery to the lungs of subjects infected via a nebulizer. Because liposome particles are small enough to penetrate and diffuse through sputum into the bacterial biofilm, they deposit drug in close proximity to the bacterial colonies, thus improving the bioavailability of amikacin at the infection site. The clinically achievable doses of amikacin in the LAI formulation can effectively increase the half-life of the drug in the lungs, and decrease the potential for systemic toxicity. LAI offers several advantages over current therapies in treating CF subjects with chronic infection caused by P. aeruginosa.

Cystic fibrosis is a genetic disease resulting from mutations in a 230 kb gene on chromosome 7 known as the cystic fibrosis transmembrane conductance regulator (CFTR). Study subjects with CF manifest pathological changes in a variety of organs that express CFTR. The lungs are frequently affected, the sequelae being chronic infections and airway inflammation. The principal goal of treatment of subjects with CF is to slow the chronic deterioration of lung function.

This is a Phase 2a study of safety, and tolerability of 28 days of daily dosing of two dose (280 mg, and 560 mg) cohorts of Arikace™ versus placebo. Study subjects will be randomized to receive either study drug or placebo (1.5% NaCl) by inhalation via a PARI eFlow® nebulizer. Cohort 1 (280mg) will complete 28 days of daily dosing with Arikace™ and 14 day post dosing safety evaluation by the Safety Committee (DSMB) before initiation of enrollment in Cohort 2 (560mg). Cohort 2 will complete 28 days of daily dosing, and a 14 day post dosing safety assessment by the DSMB to evaluate safety data. All study patients will be followed for safety, pharmacokinetics, clinical, and microbiologic activity for 28 days post completion of study treatment.

The total study period will be up to 56 days, with screening visit occurring within the preceding 14 days prior to randomization. Patients will be clinically evaluated during the first 48 hours post-randomization, and weekly for the 28 days treatment period, and during the follow up visits at study days 35, 42, 49, and 56 days to determine safety, tolerability, pharmacokinetics (PK), and clinical, and microbiologic activity.

Clinical laboratory parameters, audiology testing, clinical adverse events, and pulmonary function will be evaluated for all study subjects in order to determine the qualitative and quantitative safety and tolerability of Arikace™ compared to Placebo. Serum, urine, and sputum specimens will be collected at periodic intervals to assess PK. Additionally; sputum samples will be collected to determine changes in bacterial density. Pulmonary function testing and CFQ-R measurements will be assessed at selected time points throughout the study.

DSMB has recommended the amendment of the main study to evaluate safety and efficacy of additional cycles of treatment with Arikace™. All patients who were randomized in the main study, were compliant with the study protocol, and continue meeting study eligibility criteria can be consented to participate in the open-label extension to evaluate the safety, tolerability and efficacy of 560 mg once daily dose of Arikace™ administered for six cycles over eighteen months. Each cycle will comprise of 28 days of treatment followed by 56 days off treatment. The total extension period will be up to 518 days (74 weeks, about 18 months).

Clinical laboratory parameters, audiology testing, clinical adverse events, and pulmonary function will be evaluated for all study subjects in order to determine the longer term safety, tolerability, and efficacy of Arikace™. Serum specimens will be collected at periodic intervals to assess PK for safety. Additionally, sputum samples will be collected to determine changes in bacterial density. Pulmonary function testing and CFQ-R measurements will be assessed at selected time points throughout the study. Arikace™, Arikayce™, Liposomal Amikacin for Inhalation (LAI) and Amikacin Liposome Inhalation Suspension (ALIS) are all the same may be used interchangeably throughout the study and other studies evaluating amikacin liposome inhalation suspension.

Inclusion Criteria:

• Written informed consent obtained from patient or designated legal guardian prior to the performance of any study related procedures.
• Male or female study subjects ≥6 years of age or older
• Confirmed diagnosis of CF
• History of chronic infection with P. aeruginosa
• Study subjects must produce a screening specimen that is positive for growth of P. aeruginosa
• FEV1 ≥ 40% predicted at Screening
• SaO2 ≥ 90% at Screening while breathing room air
• Ability to comply with study medication use, study visits and study procedures as judged by the investigator
• Ability to produce sputum or be willing to undergo an induction to produce sputum for clinical evaluation
• Clinically stable with no evidence of acute upper or lower respiratory tract infection of history of pulmonary exacerbation within 4 weeks prior to screening

Key Exclusion Criteria:

• Administration of any investigational drug within 8 weeks prior to Screening
• Emergency room visit or hospitalization for CF or respiratory-related illness within 4 weeks prior to screening
• History of alcohol, medication or illicit drug abuse within the 1 year prior to screening
• History of lung transplant
• Female of childbearing potential who is lactating or is not practicing an acceptable method of birth control (e.g., abstinence, hormonal or barrier methods, partner sterilization, or IUD)
• Positive pregnancy test
• Use of any anti-pseudomonal anitbiotics (IV antibiotics, all inhalation antibiotics, oral fluoroquinolones)within the 28 days prior to screening
• Initiation of chronic therapy (i.e. TOBI®, high-dose ibuprofen, rhDNase, macrolide antibiotics) within 28 days prior to screening
• History of sputum or throat swab culture yielding Burkholderia cepacia within 2 years of Screening
• History of mycobacterial or Aspergillus infection
• Requiring treatment within 2 years prior to screening, and/or history of allergic bronchopulmonary aspergillosis.
• History of biliary cirrhosis with portal hypertension, or splenomegaly
• History of daily, continuous oxygen supplementation or requirement for more than 2 L/min at night Change in chest x-ray at screening (or within the 3 months prior to screening)