Sildenafil Trial of Exercise Performance in Idiopathic Pulmonary Fibrosis

Phase 3

Completed

Conditions: Pulmonary Fibrosis
Hypertension, Pulmonary

Interventions: Drug: Sildenafil Citrate
Other: Placebo

Registration Number: NCT00517933

Lead Sponsor: Duke University

Brief Summary: Idiopathic pulmonary fibrosis (IPF) is a chronic lung disease that affects an individual's ability to breathe. This study will evaluate the effectiveness of sildenafil, a medication that increases blood flow to the lungs, at improving breathing function, exercise capacity, and quality of life in people with advanced IPF.

Detailed Description: IPF is a disease in which fibrous tissue clogs the lungs. This eventually damages air sacs in the lungs and leads to widespread and permanent scarring of lung tissue. Individuals with IPF may experience breathing difficulties, cough, chest pain, and a decreased exercise capacity. Pulmonary hypertension, which is high blood pressure in the arteries of the lungs, affects half of all people with IPF. The fibrous tissue that clogs the lungs also blocks blood from flowing through the lungs effectively, reducing the amount of oxygen in the lungs. The fibrous tissue also reduces the lungs' ability to use what oxygen is available. These factors can cause breathing difficulties and may eventually lead to heart disease. Sildenafil is a medication that can increase blood supply to the lungs and reduce the heart's workload. The purpose of this study is to evaluate the effectiveness of sildenafil at improving breathing function, exercise capacity, and quality of life in people with advanced IPF.

This study will enroll people with advanced IPF. Participants will be randomly assigned to receive sildenafil or placebo three times a day for 12 weeks. Study visits will occur at baseline and Weeks 1, 6, and 12. At Week 12, participants will have the option to continue in the study for an additional 12 weeks. All participants who agree to continue in the study will receive sildenafil three times a day for the second 12 weeks. Study visits will occur at Weeks 13, 18, and 24. At all study visits, a physical exam and blood collection will occur. At selected visits, the following study procedures will occur: lung function testing; urine collection; a 6-minute walk test, which will measure the distance walked in a 6-minute period; and questionnaires to assess health status, breathing, and quality of life. Participants will record medication usage and symptoms in a daily diary. Study researchers will review medical records and the Social Security death index 5 years following the end of the study to determine the incidence of death among study participants.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 180

Inclusion Criteria

Clinical diagnosis of IPF
Diffusing capacity of the lung (DLCO) level less than 35% (adjusted for hemoglobin)

Exclusion Criteria

Current enrollment in another investigational study
Six-minute walk distance of less than 50 meters at screening or study entry
Difference of greater than 15% between the screening and study entry 6-minute walk distance
Acute or long-term impairment other than dyspnea (e.g., angina pectoris, intermittent claudication) that limits the ability to comply with the 6-minute walk test or other study requirements
Forced Expiratory Volume 1-second (FEV1)/forced vital capacity (FVC) ratio of less than 0.65 after bronchodilator use
Extent of emphysema greater than the extent of fibrotic change (e.g., honeycombing, reticular changes) on high-resolution computed tomography (HRCT) scan
Acute heart attack within the 6 months prior to study entry
Nitrate use
Hypersensitivity to sildenafil or any component of the formulation
Presence of aortic stenosis (AS)
Life-threatening arrhythmia within 1 month of study entry
Diabetes mellitus requiring insulin therapy
Second-degree or third-degree atrioventricular (AV) block on electrocardiogram
Severe chronic heart failure, defined by left ventricular ejection fraction (LVEF) of less than 25%
Presence of idiopathic hypertrophic subaortic stenosis (IHSS)
Hypotension (i.e., systolic blood pressure [SBP] less than 100 mm Hg or diastolic blood pressure [DBP] less than 50 mm Hg)
Uncontrolled systemic hypertension (i.e., SBP greater than 180 mm Hg or DBP greater than 100 mm Hg)
Known penile deformities or conditions (e.g., sickle cell anemia, multiple myeloma, leukemia) that may predispose participant to priapism
Aspartate aminotransferase (AST), serum glutamic pyruvic transaminase (SGPT), alanine aminotransferase (ALT), or serum glutamic oxaloacetic transaminase (SGOT) greater than three times the upper limit of normal range
Kidney impairment (i.e., creatinine clearance less than 30 mL/minute)
Current drug or alcohol dependence
Retinitis pigmentosa
History of vision loss
History of nonarteritic ischemic optic neuropathy
Recently initiated pulmonary rehabilitation within 30 days of study entry. Participants will be prohibited from starting pulmonary rehabilitation during the study. Participants who are currently undergoing maintenance pulmonary rehabilitation at study entry will be asked to maintain their levels of rehabilitation for the duration of the study.
Use of any investigational therapy as part of a clinical trial for any medical condition within 30 days of study entry
Start or change in dose of treatment for IPF investigational agent (e.g., interferon gamma-1b, pirfenidone, etanercept, N-acetylcysteine, any other investigational agent intended to treat IPF), corticosteroids, or cytotoxic agents within 30 days of study entry
Use of certain medications. More information about this criterion can be found in the study protocol.
Treatment for pulmonary hypertension with prostaglandins (e.g., epoprostenol, treprostinil), endothelin-1 antagonists (e.g., bosentan, sitaxsentan, ambrisentan), or any other phosphodiesterase inhibitor (e.g., tadalafil, vardenafil) within 30 days of study entry
Addition or discontinuation of calcium channel blockers, digitalis, diuretics, or vasodilators within 30 days of study entry (dosage must be stable for 7 days prior to study entry [except for diuretics])
Currently on the waiting list for a lung transplant
Use of L-arginine supplements
Use of grapefruit juice or St. John's wort
Pregnant or breastfeeding
Resting saturation of peripheral oxygen (SpO2) (i.e., oxygen saturation measured using pulse oximetry) less than 92% with 6 liters of supplemental oxygen

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Sildenafil	Sildenafil Citrate	20 mg of sildenafil 3 times a day (TID) for 12 weeks followed by 20 mg of sildenafil TID for an additional 12 weeks
Placebo / Sildanafil	Placebo	20 mg of placebo TID for 12 weeks followed by 20 mg of sildenafil citrate TID for an additional 12 weeks

Primary Outcome Measures

Name	Time	Method
Change in 6-minute Walk Distance From Enrollment to Week 12 (≥ 20% Improvement)	Measured at Week 12	This is a binary score (1 or 0) with 1 being better than 0. All models adjust for baseline values of age, height, sex, white race, and DLCO. Values from models are estimated changes from baseline to 12 weeks (with 95% confidence intervals). The difference estimate is based on sildenafil - placebo.

Secondary Outcome Measures

Name	Time	Method
Desaturation During 6-minute Walk Test (6MWT)	Week 12	The 6MWT was stopped when the pulse oximetry (SpO2) dropped to below 80% for six consecutive seconds. The estimates are based on the Kaplan-Meier event curves with minutes walked as the x-axis.
Change in Dyspnea	Measured from enrollment to 12 weeks (phase I)	The University of California at San Diego Shortness of Breath Questionnaire (SOBQ) uses a 6-point scale (0 = "not at all" to 5 = "maximal or unable to do because of breathlessness") to rate 24 items. The final score ranges from 0 to 120 -- lower scores are better.
Change in Forced Vital Capacity (FVC) Adjusted Values	Baseline, Week 12	Change in FVC (liters) from baseline (time 0) to week 12 comparing the sildenafil and placebo groups. Values adjusted for baseline values of age, height, sex, white race, and DLCO. Values from models are estimated changes from baseline to 12 weeks (with 95% confidence intervals). The difference estimate is based on sildenafil - placebo.
Forced Vital Capacity (FVC)	Baseline, Week 6, Week 12	Raw scores of FVC (liters) from baseline (time 0) to week 6 and 12 comparing the sildenafil and placebo groups
Diffusing Capacity of the Lung for Carbon Monoxide (DLCO)	Baseline, Week 6, Week 12	Raw scores of DLCO (% predicted) measured at baseline (time 0), week 6, and week 12 comparing the sildenafil and placebo groups
Change in Borg Dyspnea Index (BDI) After 6 Minute Walk Test (Adjusted Values)	Baseline, 12 week	The BDI was calculated by using a 10-point scale (0 = None, 10 = Maximum) and indicates the degree of breathlessness after completion of the 6-minute walk test. Values adjusted for baseline values of age, height, sex, white race, and DLCO. Values from models are estimated changes from baseline to 12 weeks (with 95% confidence intervals). The difference estimate is based on sildenafil - placebo.
Borg Dyspnea Index (BDI) After 6 Minute Walk Test (Raw Scores)	Baseline, 6 week, 12 week	The BDI was calculated by using a 10-point scale (0 = None, 10 = Maximum) and indicates the degree of breathlessness after completion of the 6-minute walk test.
Change in St. George's Respiratory Questionnaire (Total Score) (Adjusted Values)	Baseline, 12 week	The St. George's Respiratory Questionnaire asks patients how breathing problems impair their life and is scored from 0 (no impairment) to 100 (maximum impairment.) Values adjusted for baseline values of age, height, sex, white race, and DLCO. Values from models are estimated changes from baseline to 12 weeks (with 95% confidence intervals). The difference estimate is based on sildenafil - placebo.
St. George's Respiratory Questionnaire (Total Score)	Baseline, 6 weeks, 12 weeks	Mean raw scores of the St. George's Respiratory Questionnaire. The St. George's Respiratory Questionnaire asks patients how breathing problems impair their life and is scored from 0 (no impairment) to 100 (maximum impairment.)
Change in St. George's Respiratory Questionnaire (Symptoms Score) Adjusted Value	Baseline, 12 weeks	The St. George's Respiratory Questionnaire asks patients how breathing problems impair their life and is scored from 0 (no impairment) to 100 (maximum impairment). Values adjusted for baseline values of age, height, sex, white race, and DLCO. Values from models are estimated changes from baseline to 12 weeks (with 95% confidence intervals). The difference estimate is based on sildenafil - placebo.
6-minute Walk Distance (6MWT)	Baseline, 6 week, 12 week	The 6MWT measures the distance that a participant can walk in a period of 6 minutes.
Estimated Change From Baseline to 12 Weeks in 6-minute Walk Distance	Baseline, week 12	The 6MWT measures the distance that a participant can walk in a period of 6 minutes. All models adjust for baseline values of age, height, sex, white race, and DLCO. Values from models are estimated changes from baseline to 12 weeks (with 95% confidence intervals). The difference estimate is based on sildenafil - placebo.
Change in Diffusing Capacity of the Lung for Carbon Monoxide (DLCO) Adjusted Values	Baseline, Week 12	Change in DLCO (% predicted) measured at baseline (time 0), and week 12 comparing the sildenafil and placebo groups. All models adjust for baseline values of age, height, sex, white race, and DLCO. Values from models are estimated changes from baseline to 12 weeks (with 95% confidence intervals). The difference estimate is based on sildenafil - placebo.
Change in SF36 Aggregate Physical (Adjusted Value)	Baseline, 12 weeks	The SF36 measures functional health and well-being scores on eight scales that correlate with two aggregate scores. Each score ranges from 0 to 100, with a higher score indicating better function. Values adjusted for baseline values of age, height, sex, white race, and DLCO. Values from models are estimated changes from baseline to 12 weeks (with 95% confidence intervals). The difference estimate is based on sildenafil - placebo.
Short Form Health Survey (SF36) Aggregate Physical	Baseline, 6 weeks, 12 weeks	The SF36 measures functional health and well-being scores on eight scales that correlate with two aggregate scores. Each score ranges from 0 to 100, with a higher score indicating better function. Mean raw scores of SF36 Aggregate Physical.
University of California at San Diego (UCSD) Shortness of Breath Questionnaire Total	Baseline, 6 weeks, 12 weeks	The University of California at San Diego Shortness of Breath Questionnaire (SOBQ) uses a 6-point scale (0 = "not at all" to 5 = "maximal or unable to do because of breathlessness") to rate 24 items. The final score ranges from 0 to 120 -- lower scores are better. (Raw scores) Values adjusted for baseline values of age, height, sex, white race, and DLCO. Values from models are estimated changes from baseline to 12 weeks (with 95% confidence intervals). The difference estimate is based on sildenafil - placebo.
St. George's Respiratory Questionnaire (Impacts Score)	Baseline, 6 weeks, 12 weeks	The St. George's Respiratory Questionnaire asks patients how breathing problems impair their life and is scored from 0 (no impairment) to 100 (maximum impairment). Mean raw scores of the St. George's Respiratory Questionnaire.
Change in ICECAP-O Adjusted Value	Baseline, 12 weeks	The ICEpop CAPability measure for Older people (ICECAP-O) is a measure of capability in older people for use in economic evaluation. The values of ICECAP-O range from 0 (worst) to 1 (best). Values adjusted for baseline values of age, height, sex, white race, and DLCO. Values from models are estimated changes from baseline to 12 weeks (with 95% confidence intervals). The difference estimate is based on sildenafil - placebo.
ICECAP-O	Baseline, 6 weeks, 12 weeks	The ICEpop CAPability measure for Older people (ICECAP-O) is a measure of capability in older people for use in economic evaluation. The values of ICECAP-O range from 0 (worst) to 1 (best). Mean raw scores of ICECAP-O.
Change in EuroQOL Thermometer (Adjusted Value)	Baseline, 12 weeks	The thermometer score ranges from 0 (worst imaginable health state) to 100 (best imaginable health state). Higher scores indicate a better health state. Values adjusted for baseline values of age, height, sex, white race, and DLCO. Values from models are estimated changes from baseline to 12 weeks (with 95% confidence intervals). The difference estimate is based on sildenafil - placebo.
EuroQOL Thermometer	Baseline, 6 weeks, 12 weeks	The thermometer score ranges from 0 (worst imaginable health state) to 100 (best imaginable health state). Higher scores indicate a better health state. Mean raw scores of EuroQOL Thermometer.
Change in EuroQOL (EQ-5D) Utility - Adjusted Value	Baseline, 12 weeks	EQ-5D: participant rated questionnaire to assess health-related quality of life in terms of a single utility score. Health State Profile component assesses level of current health for 5 domains: mobility, self-care, usual activities, pain and discomfort, and anxiety and depression; 1 indicates better health state (no problems); 3 indicates worst health state (eg, "confined to bed"). Scoring formula developed by EuroQol Group assigns a utility value for each domain in the profile. Score is transformed and results in total score range -0.594 to 1.000; higher score indicates better health state. Values adjusted for baseline values of age, height, sex, white race, and DLCO. Values from models are estimated changes from baseline to 12 weeks (with 95% confidence intervals). The difference estimate is based on sildenafil - placebo.
St. George's Respiratory Questionnaire (Symptoms Score)	Baseline, 6 weeks, 12 weeks	The St. George's Respiratory Questionnaire asks patients how breathing problems impair their life and is scored from 0 (no impairment) to 100 (maximum impairment). Mean raw scores of the St. George's Respiratory Questionnaire. Mean raw scores of the St. George's Respiratory Questionnaire.
Change in St. George's Respiratory Questionnaire (Activity Score) Adjusted Value	Baseline, 12 weeks	The St. George's Respiratory Questionnaire asks patients how breathing problems impair their life and is scored from 0 (no impairment) to 100 (maximum impairment). Values adjusted for baseline values of age, height, sex, white race, and DLCO. Values from models are estimated changes from baseline to 12 weeks (with 95% confidence intervals). The difference estimate is based on sildenafil - placebo.
St. George's Respiratory Questionnaire (Activity Score)	Baseline, 6 weeks, 12 weeks	The St. George's Respiratory Questionnaire asks patients how breathing problems impair their life and is scored from 0 (no impairment) to 100 (maximum impairment). Mean raw scores of the St. George's Respiratory Questionnaire.
Change in St. George's Respiratory Questionnaire (Impacts Score) Adjusted Value	Baseline, 12 weeks	The St. George's Respiratory Questionnaire asks patients how breathing problems impair their life and is scored from 0 (no impairment) to 100 (maximum impairment). Values adjusted for baseline values of age, height, sex, white race, and DLCO. Values from models are estimated changes from baseline to 12 weeks (with 95% confidence intervals). The difference estimate is based on sildenafil - placebo.
EuroQOL (EQ-5D) Utility	Baseline, 6 weeks, 12 weeks	EQ-5D: participant rated questionnaire to assess health-related quality of life in terms of a single utility score. Health State Profile component assesses level of current health for 5 domains: mobility, self-care, usual activities, pain and discomfort, and anxiety and depression; 1 indicates better health state (no problems); 3 indicates worst health state (eg, "confined to bed"). Scoring formula developed by EuroQol Group assigns a utility value for each domain in the profile. Score is transformed and results in total score range -0.594 to 1.000; higher score indicates better health state. Mean raw scores of EuroQOL Utility.
Change in Short Form Health Survey (SF36) General Health - Adjusted Value	Baseline, 12 weeks	The SF36 measures functional health and well-being scores on eight scales that correlate with two aggregate scores. Each score ranges from 0 to 100, with a higher score indicating better function. Values adjusted for baseline values of age, height, sex, white race, and DLCO. Values from models are estimated changes from baseline to 12 weeks (with 95% confidence intervals). The difference estimate is based on sildenafil - placebo.
Short Form Health Survey (SF36) General Health	Baseline, 6 weeks, 12 weeks	The SF36 measures functional health and well-being scores on eight scales that correlate with two aggregate scores. Each score ranges from 0 to 100, with a higher score indicating better function. Mean raw scores of SF36 General Health

Trial Locations

Locations (13): University of California - Los Angeles
🇺🇸
Los Angeles, California, United States
Emory University
🇺🇸
Atlanta, Georgia, United States
University of Michigan
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Ann Arbor, Michigan, United States
Weill Medical College of Cornell University
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New York, New York, United States
University of California - San Francisco
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San Francisco, California, United States
University of Chicago
🇺🇸
Chicago, Illinois, United States
Duke University Medical Center
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Durham, North Carolina, United States
University of Washington
🇺🇸
Seattle, Washington, United States
Mayo Clinic
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Rochester, Minnesota, United States
Tulane University
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New Orleans, Louisiana, United States
University of Alabama - Birmingham
🇺🇸
Birmingham, Alabama, United States
National Jewish Medical and Research Center
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Denver, Colorado, United States
Vanderbilt University
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Nashville, Tennessee, United States