A novel bioresorbable polymer paclitaxel-eluting stent for the treatment of single and multivessel coronary disease: primary results of the COSTAR (Cobalt Chromium Stent With Antiproliferative for Restenosis) II study.

Objectives: The aim was to compare safety and effectiveness of the CoStar drug-eluting stent (DES) (Conor MedSystems, Menlo Park, California) with those of the Taxus DES (Boston Scientific, Maple Grove, Minnesota) in de novo single- and multivessel percutaneous coronary intervention (PCI).

Background: Paclitaxel elution from a stent coated with biostable polymer (Taxus) reduces restenosis after PCI. The CoStar DES is a novel stent with laser-cut reservoirs containing bioresorbable polymer loaded to elute 10 microg paclitaxel/30 days.

Methods: Patients undergoing PCI for a single target lesion per vessel in up to 3 native epicardial vessels were randomly assigned 3:2 to CoStar or Taxus. Primary end point was 8-month major adverse cardiac events (MACE), defined as adjudicated death, myocardial infarction (MI), or clinically driven target vessel revascularization (TVR). Protocol-specified 9-month angiographic follow-up included 457 vessels in 286 patients.

Results: Of the 1,700 patients enrolled, 1,675 (98.5%) were evaluable (CoStar = 989; Taxus = 686), including 1,330 (79%) single-vessel and 345 (21%) multivessel PCI. The MACE rate at 8 months was 11.0% for CoStar versus 6.9% for Taxus (p < 0.005), including adjudicated death (0.5% vs. 0.7%, respectively), MI (3.4% vs. 2.4%, respectively), and TVR (8.1% vs. 4.3%, respectively). Per-vessel 9-month in-segment late loss was 0.49 mm with CoStar and 0.18 mm with Taxus (p < 0.0001). Findings were consistent across pre-specified subgroups.

Conclusions: The CoStar DES is not noninferior to the Taxus DES based on per-patient clinical and per-vessel angiographic analyses. The relative benefit of Taxus is primarily attributable to reduction in TVR. Follow-up to 9 months showed no apparent difference in death, MI, or stent thrombosis rates.