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

• 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
• Drug: Placebo
  
  placebo identical to the study drug in description, dose and duration

• Experimental: Sitaxsentan sodium
  
  Intervention: Drug: Sitaxsentan sodium
• Placebo Comparator: Placebo
  
  Intervention: Drug: Placebo

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