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A Study of the Effectiveness of Sitaxsentan Sodium in Patients With Diastolic Heart Failure

This study has been completed.
ClinicalTrials.gov Identifier:
First Posted: March 17, 2006
Last Update Posted: October 11, 2012
The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
Information provided by (Responsible Party):
The aim of this study was to determine whether long-term (≥ 6 months at the target dose) blockade of ETA receptors using sitaxsentan showed functional benefit in subjects with chronic Heart Failure and an Left Ventricular Ejection Fraction ≥50%.

Condition Intervention Phase
Diastolic Heart Failure Drug: Sitaxsentan sodium Drug: Placebo Phase 2

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary Purpose: Treatment
Official Title: A Phase 2 Randomised, Double-Blind, Placebo-Controlled Exploratory Efficacy Study Of Sitaxsentan Sodium To Improve Impaired Exercise Tolerance In Subjects With Diastolic Heart Failure

Resource links provided by NLM:

Further study details as provided by Pfizer:

Primary Outcome Measures:
  • change in treadmill exercise time from baseline [ Time Frame: Baseline and month 24 ]

Secondary Outcome Measures:
  • Change in the ratio of E/E' measured by Doppler ECHO and TDI [ Time Frame: Baseline and month 24 ]
  • Change in left ventricular mass measured by ECHO [ Time Frame: Baseline and month 24 ]
  • Change in Quality of Life Assessment as measured by the MLHF [ Time Frame: Baseline and month 24 ]
  • Change in NYHA Functional Class [ Time Frame: Baseline and month 24 ]

Enrollment: 192
Study Start Date: March 2006
Study Completion Date: May 2008
Primary Completion Date: May 2008 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Sitaxsentan sodium Drug: Sitaxsentan sodium
sitaxsentan 100 mg (target dose) 0rally once daily. A 10-week Run-In Phase was conducted where dosing commenced at 25 mg daily for 2 weeks, and then was stepped up to 50 mg daily for 2 weeks, to 75 mg daily for 2 weeks and then to 100 mg daily for 2 weeks, with an additional 2-week stabilization period (10 weeks total) to a target study dose of 100 mg daily. During the Run-In Phase, if a subject was not able to tolerate upward dose titration to the target dose of 100 mg, the investigator may have elected to continue at the current dosage or reduce the dosage of sitaxsentan or placebo to the subject's immediate prior dose. During the Maintenance Phase, subjects received the highest titrated dose reached of study drug and continued it through the last day of Week M24 of the Maintenance Phase (14 weeks)- total study drug treatment duration= 6 months
Placebo Comparator: Placebo Drug: Placebo
placebo identical to the study drug in description, dose and duration


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

Inclusion Criteria:

  • 18 or older with chronic heart failure and evidence of diastolic dysfunction on echocardiogram, heart imaging, and a minimum exercise tolerance average time of 120 seconds on two treadmill tests within 2 weeks of enrollment

Exclusion Criteria:

  • unstable cardiovascular disease within 4 weeks of screening, history of heart attack, cardiac by-pass surgery or percutaneous intervention, stent placement, within 3 months of screening or amyloidosis, hypertrophic obstructive or restrictive cardiomyopathy, or constrictive pericarditis
  Contacts and Locations
Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00303498

  Show 47 Study Locations
Sponsors and Collaborators
Study Director: Pfizer CT.gov Call Center Pfizer
  More Information

Additional Information:
Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: Pfizer
ClinicalTrials.gov Identifier: NCT00303498     History of Changes
Other Study ID Numbers: B1321006
First Submitted: March 16, 2006
First Posted: March 17, 2006
Last Update Posted: October 11, 2012
Last Verified: October 2012

Additional relevant MeSH terms:
Heart Failure
Heart Failure, Diastolic
Heart Diseases
Cardiovascular Diseases
Endothelin Receptor Antagonists
Molecular Mechanisms of Pharmacological Action