Background: Tranilast is a unique drug in clinical development for the prevention of restenosis after percutaneous transluminal coronary revascularization (PTCR). Tranilast interferes with proliferation and migration of vascular medial smooth muscle cells induced by platelet-derived growth factor and transforming growth factor beta1. Collagen synthesis in vascular medial smooth muscle cells is inhibited by tranilast, which also inhibits the release or production of cyclooxygenase-2 and restores cytokine-induced nitric oxide production. These mechanisms may contribute to the reduction of angiographic restenosis after coronary intervention previously reported in clinical studies.
Methods: The primary objective of this multicenter study of 11,500 patients is to compare the composite clinical event rate of death, myocardial infarction, or the need for ischemia-driven target vessel revascularization of tranilast (300 and 450 mg twice daily) for 1 or 3 months with that of placebo in patients undergoing PTCR with or without stenting for single or multiple vessels over a 9-month period. The lesions can be de novo or restenotic. All revascularization procedures and the use of glycoprotein IIb/IIIa agents are permitted. The inclusion criteria are meant to allow an "all comer" approach for generalization of results to the broadest possible PTCR population. A subset population (n = 2000) will undergo 9-month follow-up angiography, 1000 of which will also undergo intravascular ultrasound (n = 1000). This study is the first tranilast trial to be conducted in a Western population to confirm the improved angiographic findings reported in Japanese patients and to determine if the clinical sequelae of restenosis are also reduced.
Conclusion: This multicenter study is the largest restenosis trial planned to date. It will test whether tranilast, a drug with multiple actions aimed at affecting proliferation and migration of vascular smooth muscle cells, can reduce clinical, angiographic, and intravascular ultrasound assessments of restenosis.