Safety Study of UT-15C SR (Oral Treprostinil) in Patients Undergoing a Lower Limb Endovascular Procedure

In chronic CLI patients who are appropriate candidates for endovascular procedures - and many patients are not because of their advanced age and disease state - the treatment regimen may include endovascular procedures such as percutaneous transluminal endovascular intervention, as well as reconstructive surgical procedures such as grafts or bypasses. Amputation is a last resort where limb salvage cannot be achieved. Despite the success of percutaneous intervention for small coronary vessels with lumen diameters less than 3 mm, similar techniques have had limited success in the lower extremity vessels. Infra-popliteal, or below the knee endovascular intervention, is commonly plagued by subacute thrombotic closure and restenosis in as many as 50% of treated patients. As a result of the limited success, these percutaneous procedures have been reserved for the severest cases whereby limb loss is imminent without intervention. In this context, the sickest of all patients are enrolled in these trials and poor outcomes are common regardless of the intervention. Agents that promote intracellular cAMP accumulation, including prostacyclin analogues and phosphodiesterase inhibitors, suppress smooth muscle proliferation, promote vasodilatation and inhibit platelet aggregation. These properties suggest that prostacyclin analogues such as treprostinil will be useful adjuncts to peripheral endovascular intervention and perhaps increase the number of patients with CLI that can benefit from peripheral endovascular intervention. An orally available prostacyclin analogue could represent an important treatment advance in the prevention of restenosis following infrapopliteal angioplasty. In the present study, the safety and efficacy of oral UT-15C sustained release (SR) tablets will be compared to placebo in patients with CLI undergoing an infra-popliteal endovascular intervention.