Cystic FibrosisPhase 1/2NCT00659529
Safety and Efficacy of Sildenafil in Cystic Fibrosis (CF) Lung Disease
A Phase 1/2 study testing sildenafil in people with Cystic Fibrosis, run by National Jewish Health at 1 site in United States.
Trial summary
The purpose of this study is to determine whether sildenafil can decrease inflammation in CF lung disease. Read more about this study
- Who is it for?
- Ages 14 years and older
- Conditions the study is for
- Cystic Fibrosis
- What is being tested?
- sildenafil
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 36 participants
- Where
- 1 siteUnited States
- Study dates
- Aug 2008to Dec 2012
- Phase
- Phase 1/2
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 14 years and older
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Who may be able to join
- 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 one or more clinical features consistent with the CF phenotype
- Male or female patients ≥ 12 years of age
- 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
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- 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)
Who cannot join
- History of hypersensitivity to sildenafil
- Use of an investigational agent within the 4-week period prior to Visit 1 (Day 0)
- Breastfeeding, pregnant, or verbal expression of unwillingness to practice an acceptable birth control method (abstinence, hormonal or barrier methods, partner sterilization or intrauterine device) during participation in the study
- Daily use of systemic corticosteroids and/or NSAIDs within 4 weeks of the study or as needed use within 72 hours prior to the screening visit
- History of significant hepatic (SGOT or SGPT > 3 times the upper limit of normal at screening, documented biliary cirrhosis, or portal hypertension), cardiovascular (history of aortic stenosis, coronary artery disease, pulmonary hypertension with right ventricular systolic pressure >55 mmHg or life-threatening arrhythmia), neurological (history of stroke), hematologic (history of bleeding diathesis), ophthalmologic (history of retinal impairment or non-arteritic ischemic optic neuritis) or renal impairment (creatinine >1.8 mg/dL.)
- Inability to swallow pills
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- Previous lung transplantation
- Use of concomitant nitrates, α-blocker, or Ca channel blocker
- Use of concomitant medications known to be potent inhibitors of CYP3A4 (e.g. ketoconazole, itraconazole, ritonavir, clarithromycin, erythromycin, rifampin)
- Presence of a condition or abnormality that in the opinion of the investigator would compromise the safety of the subject or the quality of the data
- Weight less than 40 kg
- History of sputum or throat swab culture yielding Burkholderia cepacia within 2 years of screening
- Resting room air oxygen saturation <93%
- History of migraines
Trial locations and contacts
1 site in 1 country.
About this study
Official title: The Role of Phosphodiesterase Inhibitors in CF Lung Disease
The purpose of this study is to determine whether sildenafil can decrease inflammation in CF lung disease.
Read the detailed description
This study is an open-label study that examines the use of sildenafil (Revatio) in clinically stable patients with mild to moderate CF lung disease. The length of participation for each subject will be approximately 10 weeks, and will consist of a screening visit, a study visit for initiation of study drug if subject qualifies, interim visits to escalate drug dose, obtain drug levels, review concomitant medications and assess side effects, a visit at the end of the therapy period (to reassess inflammatory markers, laboratory studies and side effects,) and a follow-up assessment 2 weeks after subject completion.
- Conditions
- Cystic Fibrosis
- Being tested
- sildenafil
- Keywords
- cystic fibrosis, inflammation, pH, EBC, sputum biomarkers, phosphodiesterase inhibitors
- Medical subject headings
- Cystic Fibrosis, Inflammation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
sildenafilDrug
Also called Revatio
Sildenafil will be given 20mg po tid for 1 week, and then will be give 40mg po tid for 5 weeks.
| Study group | Role | What they receive |
|---|---|---|
| Pilot study of systemic sildenafil administration to people with cystic fibrosis | Experimental | This is a study of sildenafil administration to patients with mild to moderate cystic fibrosis (CF). 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 to evaluate safety, tolerability, pharmacokinetics in people with CF, and surrogate markers of pulmonary function. Receives: Drug: sildenafil |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Sputum Elastase Activity
Exploratory analysis for efficacy of sildenafil on sputum biomarkers of inflammation, including sputum elastase. This measure will indicate whether sildenafil will increase or decrease sputum elastase activity.
Measured: Baseline and 6 weeks
Secondary outcomes (2)
Change in Exhaled Breath Condensate pH
Endogenous airway acidification can be assessed by measuring pH in exhaled breath condensate, a non-invasive measure of response to therapy. This measure will indicate whether sildenafil will improve, worsen, or cause no change in exhaled breath condensate pH.
Measured: Baseline and 6 weeks
Change in Cystic Fibrosis Questionnaire - Revised (CFQ-R) Respiratory Domain, Average Unit Change From Baseline to 6 Weeks is Reported
The CFQ-R is designed to measure CF-specific patient-reported health-related quality of life. It is a validated CF-specific quality of life measure. The CFQ-R Respiratory domain score (scale 0-100 with higher scores indicating better quality of life). This measure will indicate whether sildenafil will improve, worsen, or cause no change in the CFQ-R respiratory domain scores from baseline at 6 weeks.
Measured: 6 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted16 Apr 2008 (estimated)
- Study startAug 2008
- Primary completionAug 2012
- Study completionDec 2012
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for Cystic FibrosisStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1/2
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 36 participants (actual)
Sponsor and investigators
- Lead sponsor
- National Jewish Health
- Sponsor type
- University, hospital or other
- Collaborators
- Cystic Fibrosis Foundation
- Responsible party
- Principal investigator, Jennifer Taylor-Cousar, National Jewish Health
- Investigators
- Jennifer L Taylor-Cousar, MD, Principal investigator, National Jewish Health
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00659529
- Sponsor's protocol ID
- 851R14-8510M3
- Status last verified
- May 2026
- First submitted
- 14 Apr 2008
- Last updated
- 14 May 2026
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- Yes
- Individual data sharing
- No
Publications
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. doi: 10.1152/ajplung.00314.2006. Epub 2007 Jun 22.
PubMed 17586695Taylor-Cousar JL, Wiley C, Felton LA, St Clair C, Jones M, Curran-Everett D, Poch K, Nichols DP, Solomon GM, Saavedra MT, Accurso FJ, Nick JA. Pharmacokinetics and tolerability of oral sildenafil in adults with cystic fibrosis lung disease. J Cyst Fibros. 2015 Mar;14(2):228-36. doi: 10.1016/j.jcf.2014.10.006. Epub 2014 Nov 13.
PubMed 25466700
Study at a glance
From the registry record, last updated by the sponsor on 14 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Role of Phosphodiesterase Inhibitors in CF Lung Disease
- ClinicalTrials.gov ID
- NCT00659529
- Acronym / sponsor ID
- 851R14-8510M3
- Conditions
- Cystic Fibrosis
- Keywords
- cystic fibrosis, inflammation, pH, EBC, sputum biomarkers, phosphodiesterase inhibitors
- Phase
- Phase 1/2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 36 participants (actual)
- Lead sponsor
- National Jewish HealthUniversity, hospital or other
- Collaborators
- Cystic Fibrosis Foundation
- Study start
- Aug 2008 (actual)
- Primary completion
- Aug 2012 (actual)
- Study completion
- Dec 2012 (actual)
- First posted
- 16 Apr 2008 (estimated)
- Results
- Posted 2 May 2014
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this study is to determine whether sildenafil can decrease inflammation in CF lung disease.
Detailed description
This study is an open-label study that examines the use of sildenafil (Revatio) in clinically stable patients with mild to moderate CF lung disease. The length of participation for each subject will be approximately 10 weeks, and will consist of a screening visit, a study visit for initiation of study drug if subject qualifies, interim visits to escalate drug dose, obtain drug levels, review concomitant medications and assess side effects, a visit at the end of the therapy period (to reassess inflammatory markers, laboratory studies and side effects,) and a follow-up assessment 2 weeks after subject completion.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Pilot study of systemic sildenafil administration to people with cystic fibrosis | Experimental | Drug: sildenafilThis is a study of sildenafil administration to patients with mild to moderate cystic fibrosis (CF). 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 to evaluate safety, tolerability, pharmacokinetics in people with CF, and surrogate markers of pulmonary function. |
Who may qualify
- Ages
- 14 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
Key inclusion criteria (10 listed)
- Confirmed diagnosis of CF based on the following criteria:
- Male or female patients ≥ 12 years of age
- 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)
Key exclusion criteria (14 listed)
- History of hypersensitivity to sildenafil
- Use of an investigational agent within the 4-week period prior to Visit 1 (Day 0)
- Breastfeeding, pregnant, or verbal expression of unwillingness to practice an acceptable birth control method (abstinence, hormonal or barrier methods, partner sterilization or intrauterine device) during participation in the study
- Daily use of systemic corticosteroids and/or NSAIDs within 4 weeks of the study or as needed use within 72 hours prior to the screening visit
- History of significant hepatic (SGOT or SGPT > 3 times the upper limit of normal at screening, documented biliary cirrhosis, or portal hypertension), cardiovascular (history of aortic stenosis, coronary artery disease, pulmonary hypertension with right ventricular systolic pressure >55 mmHg or life-threatening arrhythmia), neurological (history of stroke), hematologic (history of bleeding diathesis), ophthalmologic (history of retinal impairment or non-arteritic ischemic optic neuritis) or renal impairment (creatinine >1.8 mg/dL.)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| sildenafilAlso: RevatioSildenafil will be given 20mg po tid for 1 week, and then will be give 40mg po tid for 5 weeks. | Drug | Pilot study of systemic sildenafil administration to people with cystic fibrosis |
Primary outcome
Change in Sputum Elastase Activity
Time frame: Baseline and 6 weeks
Exploratory analysis for efficacy of sildenafil on sputum biomarkers of inflammation, including sputum elastase. This measure will indicate whether sildenafil will increase or decrease sputum elastase activity.
2 secondary outcomes
Change in Exhaled Breath Condensate pH
Time frame: Baseline and 6 weeks
Change in Cystic Fibrosis Questionnaire - Revised (CFQ-R) Respiratory Domain, Average Unit Change From Baseline to 6 Weeks is Reported
Time frame: 6 weeks
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 14 May 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Background: PubMed 17586695Poschet 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. doi: 10.1152/ajplung.00314.2006. Epub 2007 Jun 22.
- Derived from this study: PubMed 25466700Taylor-Cousar JL, Wiley C, Felton LA, St Clair C, Jones M, Curran-Everett D, Poch K, Nichols DP, Solomon GM, Saavedra MT, Accurso FJ, Nick JA. Pharmacokinetics and tolerability of oral sildenafil in adults with cystic fibrosis lung disease. J Cyst Fibros. 2015 Mar;14(2):228-36. doi: 10.1016/j.jcf.2014.10.006. Epub 2014 Nov 13.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Jennifer L Taylor-Cousar, MD principal investigator
National Jewish Health
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1/2 study testing sildenafil in people with Cystic Fibrosis, run by National Jewish Health at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 10 inclusion and 14 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 14 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this combined phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 2 May 2014). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in Sputum Elastase Activity (time frame: Baseline and 6 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT00659529, which also lists 2 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 14 May 2026.