Trial of Aeroquin Versus Tobramycin Inhalation Solution (TIS) in Cystic Fibrosis (CF) Patients

This study will assess the comparative safety of MP-376 (Aeroquin) and Tobramycin Inhalation
solution (TIS) [TOBI® Novartis Pharmaceuticals] over three consecutive cycles of 28-days
treatment followed by 28-days off in stable CF patients with chronic P. aeruginosa lung
infection. Efficacy data for MP-376 and TIS at the end of the first 28-day treatment period
will also be compared, as well as explored over multiple treatment cycles.

Study patients participating in Mpex 209 will be given the option to participate in a
six-month open label extension phase of the Mpex 209 protocol. The open label extension will
allow enrolled patients to receive three additional courses of MP-376 (levofloxacin
inhalation solution, Aeroquin™).

Inclusion Criteria (selected):

- > 12 years of age

- Confirmed Diagnosis of Cystic Fibrosis

- Positive sputum culture for P. aeruginosa within the past 12 months

- Patients are able to elicit an FEV1 >/= 25% but screening

- Have received at least 3 courses of inhaled tobramycin over the preceding 12 months

- Clinically stable with no changes in health status within the last 28 days

- Able to reproducibly produce sputum and perform spirometry

Exclusion Criteria (selected):

- Use of any nebulized or systemic antibiotics within 28 days prior to baseline

- History of hypersensitivity to fluoroquinolones or inhaled or systemic aminoglycosides
including tobramycin or any excipients

- Evidence of acute upper within 10 days or lower respiratory infections within 28 days
prior to dosing

- CrCl < 20 at Screening

- History of lung transplantation

Extension Portion of the Study: Patients enrolled in Mpex 209 are permitted to participate
in the open label extension as long as they complete Visit 7 (Day 168), provide informed
consent for participation in the open label extension of in the study and are clinically
stable, as assessed by the Investigator.