TAXUS V Clinical Trial Generates Excellent Safety and Efficacy Data in Most Challenging Lesions and High-Risk Patients

Findings from the TAXUS V Clinical Trial were presented at the recent American College of Cardiology meeting. What is the TAXUS V Clinical Trial, and how is it different from previous clinical trials of drug-eluting stents (DES)? TAXUS V is a randomized, controlled trial that evaluated the performance of the TAXUS® Express2 Stent for the treatment of coronary artery blockages in real-world clinical practice situations. It stands apart from other DES trials because it included the most complex patients, procedures and lesions ever studied in a randomized, controlled trial of a DES in the United States. Approximately 30 percent of the patient population had diabetes. More than three-quarters of target lesions were AHA/ACC type B2 or C, and one-third were calcified. Target vessels were as small as 2.25 mm in diameter and total stent length was as long as 84 mm, which is significantly longer than any other U.S. DES trial (Figure 1). Many lesions (35 percent) required implantation of multiple overlapping stents. Thus, the TAXUS V Clinical Trial significantly expanded the frontiers of DES clinical research What were the major findings of the TAXUS V Clinical Trial? Patients randomized to the TAXUS Clinical Trial showed consistent safety and efficacy data at nine months. Target Vessel Revascularization (TVR) was 12.1 percent in the TAXUS Stent group versus 17.3 percent in the control group, a statistically and clinically significant difference. The overall Major Adverse Cardiac Events (MACE) rate was 15 percent in the TAXUS Stent group particularly low for such a complex set of patients compared with 21.2 percent in the control group. This reduction was due to a significantly lower Target Lesion Revascularization (TLR) rate of 8.6 percent among TAXUS Stent patients, compared with 15.7 percent among control patients. The study reported an in-segment binary restenosis rate of 18.9 percent in the TAXUS Stent group and 33.9 percent in the control group. In-stent binary restenosis was measured at 13.7 percent in the TAXUS Stent patients and 31.9 percent in patients receiving bare metal stents. Why did the study include in-segment analyses as well as in-stent analyses? In-segment analyses such as Target Lesion Revascularization (TLR) provide a more accurate indication of DES performance, since it reflects restenosis in the region of the blood vessel that has been most affected by the implantation of the stent, including not only the stented area, but also five mm on either side of the stent. From the patient’s perspective, it is irrelevant whether restenosis occurs only inside the stent or on the outside edges of the stent, which are excluded from in-stent analyses. What matters is that the patient requires additional percutaneous coronary intervention (PCI) or bypass surgery. Clinically, TLR is the most relevant measure, but with both types of endpoints included in the study, the data provide the most comprehensive analysis of DES performance. There has been some discussion about the risk of sub-acute thrombosis with TAXUS Stents. What were the findings of TAXUS V regarding thrombosis? Sub-acute thrombosis occurred infrequently in this study. Overall, stent thrombosis rates were identical between the TAXUS Stent and control stents 0.7 percent at nine months indicating comparable safety profiles of thrombosis (Figure 2). There was also zero percent thrombosis in planned overlapping stents and no late thrombosis in the TAXUS Stent arm. Such low thrombosis rates are especially striking in a complex patient population with multiple risk factors for thrombosis, such as diabetes and long lesions. Late loss has been the subject of much discussion and debate recently. What were the findings of the TAXUS V Clinical Trial in regard to this measurement? As perhaps would be expected given the complexity of lesions studied, the in-stent late loss in the Taxus Stent group in the Taxus V Clinical Trial was somewhat higher (0.49 mm) than that seen in Taxus IV (0.39 mm). Nonetheless, the relative reduction in late loss was still approximately 50 percent. For most patients, this remained well below the 0.6-1.0 mm threshold wherein the risk of TLR begins to become apparent. Why is this study important, and what are its implications for cath labs? The TAXUS V Clinical Trial provides invaluable, scientifically rigorous insights into the performance of the TAXUS Express2 Stent in the types of complex patients, lesions and procedures encountered in the cath lab every day. New insights into the performance of the 2.25 mm and 4.0 mm TAXUS Stent and overlapping stents, in particular, were provided. Data from this study will provide interventional cardiologists and cath lab staff with a greater base of knowledge and greater confidence when tackling tough clinical situations. Sponsored by Boston Scientific Corporation.

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