Conditions: Coronary Artery Disease Endothelial Dysfunction
Keywords: atherosclerosis coronary artery disease myocardial perfusion defect endothelial dysfunction endothelin receptor blockade
Allocation: RANDOMIZED | Intervention model: CROSSOVER
Enrollment: 40
Healthy volunteers: no

Brief summary:
The primary objective of this study is to test the hypothesis that myocardial perfusion heterogeneity, quantified by Markovian Homogeneity analysis of cardiac PET perfusion images, will improve in a quantitative manner after treatment with selective ETA receptor antagonist darusentan 100 mg per day for 2 weeks compared to baseline and post-treatment PET scans in clinically stable subjects with coronary atherosclerosis and/or risk factors.

Detailed description:
This 6-week, Phase 2, randomized, double-blind, crossover, investigator-initiated, single-center study will determine the feasibility of detecting the effect of darusentan 100 mg once daily on the extent of myocardial perfusion heterogeneity in subjects with documented CAD, as measured by cardiac PET imaging. Prior to the initiation of any study procedures, an Informed Consent Form and HIPAA Authorization will be reviewed and signed by each subject. Screening assessments and evaluations may be conducted over a period of not more than 4 weeks.

Following a baseline PET scan (PET 1) subjects will be randomized to one of two treatment groups (Group 1 or Group 2), and receive blinded treatment for a total of 4 weeks. The 4-week treatment period will have two phases, Phase 1 and Phase 2. Group 1 will receive darusentan 100 mg for 2 weeks during Phase 1, then placebo for 2 weeks during Phase 2. Group 2 will receive placebo for 2 weeks during Phase 1, then darusentan 100 mg for 2 weeks during Phase 2. Following 4 weeks of treatment with blinded study drug, subjects in both treatment groups will be withdrawn from study drug for an additional 2 weeks. Maximum darusentan exposure in this study will be 2 weeks, and maximum placebo exposure in this study will be 2 weeks. Adjustments to the number or dosage of concomitant medications required for study entry will not be permitted at any time during the study.

A physical exam will be done at baseline and week 6 as well as blood chemistry and hematology samples taken. Vital signs and any adverse events will be monitored at each visit.

Efficacy will be assessed through cardiac PET imaging. In total, four PET scans will be administered: the first at the Randomization Visit (PET 1, Week 0); the second at the conclusion of Phase 1 (PET 2, Week 2); the third at the conclusion of Phase 2 (PET 3, Week 4) and the fourth at the conclusion of the Withdrawal period (PET 4, Week 6).

Subjects will be instructed to take their study drug with or without food once daily at approximately the same time in the morning throughout the course of the study. Subjects will also be instructed to take all concomitant medications consistently and at the same time each day throughout the study.

Arms:
arm 1: Group 1 will receive oral darusentan 100mg for 2 weeks during Phase 1 then placebo for 2 weeks during Phase 2. arm 2: Group 2 will receive placebo for 2 weeks during Phase 1 then oral darusentan 100 mg for two weeks during Phase 2

Interventions: intervention 1: darusentan 100 mg
Intervention descriptions: intervention 1: All subjects will receive oral darusentan 100 mg for a total of 2 weeks and placebo for 2 weeks.

Protocol document: