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To Assess The Efficacy and Safety Of Oral Sildenafil in the Treatment of Pulmonary Arterial Hypertension.

This study has been terminated.
(This study was terminated at the recommendation of an independent Data Monitoring Committee. The decision was not based on any safety concerns.)
Information provided by:
Pfizer Identifier:
First received: January 31, 2007
Last updated: May 25, 2011
Last verified: May 2011
To demonstrate a dose response for 1 mg, 5 mg and 20 mg TID oral sildenafil for the treatment of subjects with PAH.

Condition Intervention Phase
Pulmonary Arterial Hypertension Drug: Sildenafil citrate Phase 4

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple (Participant, Care Provider, Investigator)
Primary Purpose: Treatment
Official Title: A Multinational, Multicentre, Randomized, Parallel Group, Double-Blind Study To Assess The Efficacy and Safety Of 1 mg, 5 mg and 20 mg TID of Oral Sildenafil in the Treatment of Subjects Aged 18 Years and Over With Pulmonary Arterial Hypertension (PAH)

Resource links provided by NLM:

Further study details as provided by Pfizer:

Primary Outcome Measures:
  • Change From Baseline in the Total Distance Walked During 6MWT at Week 12 [ Time Frame: Baseline and Week 12 ]
    6 MWT was the distance that a participant could walk in 6 minutes. Participants were asked to perform the test at a pace that was comfortable to them, with as many breaks as they needed. Continuous pulse oximetry was conducted during the test for safety.

Secondary Outcome Measures:
  • Change From Baseline in mPAP at Week 12 [ Time Frame: Baseline and Week 12 ]
    mPAP was measured using a pressure transducer positioned at the mid-axillary line.

  • Time to Clinical Worsening [ Time Frame: Baseline through Week 12 ]
    Clinical worsening was defined as death; or lung transplantation; or hospitalization due to pulmonary hypertension; or initiation of prostacyclin therapy; or initiation of endothelin receptor antagonist therapy.

  • Number of Participants With Change From Baseline in PAH Criteria for Functional Capacity and Therapeutic Class at Week 12 [ Time Frame: Baseline and Week 12 ]
    PAH Criteria for WHO Class: Class I (Participants without resulting limitation of physical activity);Class II (Participants with slight limitation of physical activity though comfortable at rest);Class III (Participants with marked limitation of physical activity,though comfortable at rest);Class IV(Participants with inability to carry out any physical activity without symptoms,manifest signs of right heart failure; dyspnoea and/or fatigue may even be present at rest; and discomfort is increased by any physical activity).

  • Change From Baseline in BNP at Week 12 [ Time Frame: Baseline and Week 12 ]
    BNP is a non-invasive biomarker and an indicator of progression of PAH/ RV dysfunction in participants with PAH.

  • Change From Baseline in Pro-BNP at Week 12 [ Time Frame: Baseline and Week 12 ]
    Pro- BNP which is a precursor of BNP, is a non-invasive biomarker and an indicator of progression of PAH / RV dysfunction in participants with PAH.

  • Change From Baseline in TAPSE Measurement at Week 12 [ Time Frame: Baseline and Week 12 ]
    TAPSE was measured as the total displacement of the tricuspid annulus in cm from end diastole to end systole.TAPSE is an indicator of progression of PAH / RV dysfunction.

  • Change From Baseline in BORG Dyspnoea Score at Week 12 [ Time Frame: Baseline and Week 12 ]
    BORG dyspnoea scale is a 10-point scale where following scores stands for severity of dyspnoea: 0 (no breathlessness at all); 0.5 (very very slight [just noticeable]); 1 (very slight); 2 (slight breathlessness); 3 (moderate); 4 (some what severe); 5 (severe breathlessness); 7 (very severe breathlessness); 9 (very very severe [almost maximum] and 10 (maximum).

Enrollment: 130
Study Start Date: April 2008
Study Completion Date: May 2010
Primary Completion Date: May 2010 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Sildenafil High dose Drug: Sildenafil citrate
oral, 20 mg, tid
Experimental: Sildenafil Low dose Drug: Sildenafil citrate
oral 1 mg, tid
Experimental: Sildenafil medium dose Drug: Sildenafil citrate
oral 5 mg, tid
Experimental: Sildenafil - Open label Phase
Open label extension from week 12 to week 24.
Drug: Sildenafil citrate
oral 20 mg, tid


Ages Eligible for Study:   18 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Subjects with PAH (i.e. IPAH or secondary to connective tissue disease or with surgical repair of ASD, VSD, PDA, aorto-pulmonary window) whose baseline six minute walk test distance is >/= 100 m and </= 450 m.
  • Subjects with a mean pulmonary artery pressure of >/= 25 mmHg and a pulmonary artery wedge pressure of </= 15 mmHg at rest via right heart catheterization performed within 12 weeks prior to randomization.

Exclusion Criteria:

  • Subjects whose 6 Minute Walk Distance may be limited by conditions other than PAH related dyspnoea or fatigue, e.g. claudication from vascular insufficiency or significant arthritis.
  • Subjects who are currently receiving any forms of chronic treatment for PAH such as prostacyclin, PDE-5 inhibitors, endothelin-receptor antagonists, nitrates or nitric oxide donors (e.g. arginine supplement, nicorandil) in any form, protease inhibitors such as ritonavir and saquinavir, ketoconazole, itraconazole, and alpha blockers. Subjects previously receiving any of these drugs must have stopped use for a period of at least 1 month prior to screening, except in the case of bosentan or prostacyclin (3 months).
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT00430716

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Sponsors and Collaborators
Study Director: Pfizer Call Center Pfizer
  More Information

Additional Information:
Responsible Party: Director, Clinical Trial Disclosure Group, Pfizer Inc Identifier: NCT00430716     History of Changes
Other Study ID Numbers: A1481244
Study First Received: January 31, 2007
Results First Received: April 22, 2011
Last Updated: May 25, 2011

Additional relevant MeSH terms:
Familial Primary Pulmonary Hypertension
Vascular Diseases
Cardiovascular Diseases
Hypertension, Pulmonary
Lung Diseases
Respiratory Tract Diseases
Citric Acid
Sildenafil Citrate
Calcium Chelating Agents
Chelating Agents
Sequestering Agents
Molecular Mechanisms of Pharmacological Action
Vasodilator Agents
Phosphodiesterase 5 Inhibitors
Phosphodiesterase Inhibitors
Enzyme Inhibitors
Urological Agents processed this record on August 21, 2017