Effect of Losartan in Cystic Fibrosis (CF)-NIH Grant #133240

Prior treatment

• Received an investigational drug or therapy during the preceding 30 days
• Treatment with angiotensin converting enzyme (ACE) inhibitor
• Oral corticosteroid use within 6 weeks
• Concomitant airway disorders other than CF, such as ABPA
• Subjects with prior thoracic surgery
• Patients using intermittent inhaled or oral antibiotics will be allowed to participate in this trial. Patients on chronic, cycling antibiotics will be required to have completed at least 2 full cycles of the prescribed antibiotic prior to enrollment and should be studied during the same phase of treatment (on or off) during each study period.
• Have had radiation exposure within the past year that would cause them to exceed Federal Regulations by participating in this study.

Other illness

• If female, patient must be non-pregnant and non-lactating, and those of childbearing potential must be using an acceptable method of birth control (i.e., an Intrauterine Contraceptive Device with a failure rate of \<1%, hormonal contraceptives or a barrier method). If a female patient is abstinent, she must agree to use one of the acceptable methods if she becomes sexually active.
• Unstable lung disease: As defined by a change in medical regimen during the preceding 2 weeks or an FEV1 ≥15% below value within 3 months
• Treatment of mycobacterial infections
• Significant hypoxemia (oxygen saturation \<92% on room air and rest or use of continuous oxygen treatment), chronic respiratory failure by history (pCO2 \> 45 mmHg), clinical evidence of cor pulmonale
• Untreated arterial hypertension (systolic blood pressure \>140 mm Hg, diastolic blood pressure \> 90 mmHg)

Lab values

• Regular use of NSAIDs or potassium supplementation, treatment with aliskiren, on anticoagulation
• Cardiac, renal (creatinine 1.5 times normal limit), hepatic (LFTs \> 3x normal upper limit), neurological, psychiatric, endocrine or neoplastic diseases that are judged to interfere with participation in study
• Other severe acute or chronic medical or psychiatric condition or laboratory abnormality that may increase the risk associated with trial participation or may interfere with the interpretation of trial results and, in the judgment of the PI, would make the subject inappropriate for enrollment.

Other

• When enrolling female patients
• Not willing to adhere to strict birth control (combination of two methods)
• Active or former smokers with less than 1 year since quitting, or \>10 pack-year smoking history
• Unable to adequately complete study measures, including spirometry
• Intolerance to angiotensin receptor blockers (ARB)
• Exacerbation requiring treatment within 6 weeks
• Blood pressure less than 90 mm Hg systolic while standing
• Known renal artery stenosis

• CF patients with any known mutation combination not on CFTR augmentation therapy
• ≥18 years of age
• Severity of the Disease: Suitable patients will have mild to moderate lung disease, as defined by:
  • Pulmonary Function: Each patient must have an FEV1 ≥40% of predicted at the screening visit.
  • Hemoglobin saturation: Patients must have an oxygen saturation of \>92% on room air as determined by pulse oximetry at the screening visit.
  • Produces sputum regularly (daily basis, at minimum)
• FEV1 ≥ 40% of predicted at screening visit
• Able to sign Informed consent
• Negative COVID-19 test within 72 hours prior to MCC testing