Trial of Doxycycline to Reduce Sputum MMP-9 Activity in Adult Cystic Fibrosis (CF) Patients

A Randomized Trial of Doxycycline to Reduce Sputum MMP-9 Activity in Adult CF Patients Hospitalized for Pulmonary Exacerbations

The purpose of this study is to examine the role of a well-known and well-tolerated antibiotic, doxycycline, in the treatment of cystic fibrosis patients who are hospitalized. This antibiotic does not effectively treat the bacteria in airways of cystic fibrosis patients, but may reduce the activity of inflammatory molecules in the disease.

One molecule that is inhibited by doxycycline is matrix metalloprotease-9, which is emerging as an important mediator of lung inflammation and damage in cystic fibrosis. We hypothesize that the addition of treatment with doxycycline in CF inpatients will reduce MMP-9 activity and inflammatory markers in the sputum of cystic fibrosis patients compared to CF patients not treated with doxycycline.

Inclusion Criteria:

• Cystic Fibrosis
• Hospitalization for Pulmonary exacerbation

Exclusion Criteria:

• Significant GI illness
• Participation in another Investigational Protocol
• Allergies to Doxycycline
• Sputum Culture only positive for Staphylococcus aureus,
• Pregnant or Nursing
• Unwilling to use effective birth control
• Elevated LFT's greater than 3x the upper limit of normal
• Creatinine greater than 1.5x the upper limit of normal
• Lung transplantation
• Substance abuse within 30 days of screening