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Drug & research development » Clinical trials » NCT00659529

Safety and Efficacy of Sildenafil in Cystic Fibrosis (CF) Lung Disease

Official title: The Role of Phosphodiesterase Inhibitors in CF Lung Disease

Clinical Trials gov number: NCT00659529

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Purpose: To determine whether sildenafil can decrease inflammation in CF lung disease.

Phase: 1

Type: Interventional, open-label, single group assignment

Study sponsor: National Jewish Health; Cystic Fibrosis Foundation Therapeutics

  • Confirmed diagnosis of CF based on the following criteria:

– Positive sweat chloride ≥60mEq/liter (by pilocarpine iontophoresis) and/or

– Genotype with two identifiable mutations consistent with CF, and accompanied by ≥1 clinical feature(s) consistent with the CF phenotype

  • FEV1 ≥50% predicted (Knudson) 31
  • Clinically stable without evidence of acute upper or lower respiratory tract infection or current pulmonary exacerbation within the 14 days prior to the screening visit
  • Ability to reproducibly perform spirometry (according to ATS criteria)
  • Ability to produce at least 1mL of sputum spontaneously, or be willing to undergo sputum induction
  • Ability to understand and sign a written informed consent or assent and comply with the requirements of the study
  • Chronic bacterial colonization (3 documented positive cultures in the prior 2 years of which at least one was obtained in the 3 months prior to randomization)


Geographical Location
United States

Number of Participants
≤50 (≥14 years)

Primary Endpoint

Sputum elastase

Secondary Endpoint

  • Exhaled breath condensate pH
  • CF Questionnaire-Revised
  • Serum sildenafil levels

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  • Experimental: 1

All subjects will receive oral sildenafil three times per day during the study. Study endpoints will be measured before the treatment period and at the end of the treatment period.

Sildenafil will be given 20mg po tid for 1 week, and then will be give 40mg po tid for 5 weeks.



Poschet JF, Timmins GS, Taylor-Cousar JL, Ornatowski W, Fazio J, Perkett E, Wilson KR, Yu HD, de Jonge HR, Deretic V. Pharmacological modulation of cGMP levels by phosphodiesterase 5 inhibitors as a therapeutic strategy for treatment  of respiratory pathology in cystic fibrosis. Am J Physiol Lung Cell Mol Physiol.  2007 Sep;293(3):L712-9. Epub 2007 Jun 22. PubMed PMID: 17586695.

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