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).