SPIRIT IV Safety and Efficacy Results Published and Cost-Effectiveness Analysis Presented

May 5, 2010—Abbott Vascular (Santa Clara, CA) announced that Gregg W. Stone, MD, et al have published findings from the SPIRIT IV trial in the New England Journal of Medicine (2010;362:1663–1674). Abbott Vascular also announced that David Cohen, MD, presented findings from a retrospective cost-effectiveness analysis of SPIRIT IV data on March 13 at the Cardiovascular Research Foundation's Optimizing PCI Outcomes symposium in Atlanta.

According to the company, the published SPIRIT IV study results show that 1 year after a stenting procedure, patients treated with Abbott's Xience V everolimus-eluting coronary stent system were significantly less likely to have a major adverse event such as a myocardial infarction, repeat procedure, or cardiac death compared to patients treated with a Taxus Express² paclitaxel-eluting coronary stent system (Boston Scientific Corporation, Natick, MA). The SPIRIT IV trial also showed that patients treated with Xience V were considerably less likely to experience stent thrombosis compared to patients treated with the Taxus Express².

Dr. Stone originally presented these results on September 23, 2009 at the Transcatheter Cardiovascular Therapeutics (TCT) conference in San Francisco, which was reported by Cardiac Interventions Today .

Boston Scientific markets the Promus everolimus-eluting coronary stent system, a private-label version of Xience V, designed and manufactured by Abbott and supplied to Boston Scientific as part of a distribution agreement between the two companies.

At the TCT meeting in September, Boston Scientific stated that it welcomed the 1-year data from the SPIRIT IV clinical trial, which also support the benefits of paclitaxel-eluting stents in diabetic patients, who comprised more than one-quarter of the study population. On October 1, Boston Scientific also announced the commencement of the previously planned, phased discontinuation of the Taxus Express² stent that was used in the SPIRIT IV trial. The Express stent has been replaced in the company's product line by the thinner-strut Taxus Liberté stent worldwide. The Liberté stent was approved in Europe in 2005, in the United States in 2008, and in Japan in 2009.

In the SPIRIT IV trial's primary endpoint, Xience V demonstrated a 38% reduction of target lesion failure (TLF) compared to Taxus Express² at 1 year (4.2% vs 6.8%; P = .001). TLF is defined as a composite of cardiac death, target vessel myocardial infarction, and ischemia-driven target lesion revascularization. The SPIRIT IV trial also found that the 1-year rate of stent thrombosis with Xience V is among the lowest reported to date with any drug-eluting stent (0.29% per Academic Research Consortium [ARC] definition of definite/probable stent thrombosis).

In a subgroup analysis of more than 1,100 patients with diabetes, Xience V demonstrated a lower TLF rate compared to Taxus Express² at 1 year (6.4% vs 6.9%; P = .8). In the safety endpoint of stent thrombosis, Xience V demonstrated a 40% reduction compared to Taxus Express² in patients with diabetes (per ARC definition of definite/probable stent thrombosis, 0.8% vs 1.33%; P = .52). Xience V also demonstrated a 46% reduction in target lesion revascularization rates, a major secondary endpoint, compared to Taxus Express² at 1 year (2.5% vs 4.6%; P = .001).

Per protocol definition of stent thrombosis at 1 year, Xience V demonstrated an observed 80% reduction compared to Taxus Express² (0.17% vs 0.85%; P = .004). Per ARC definition of definite/probable stent thrombosis, Xience V demonstrated an observed 74% reduction compared to Taxus Express² at 1 year (0.29 vs 1.1%; P = .004).

The SPIRIT IV cost-effectiveness analysis was based on a retrospective review of prospectively collected medical resource utilization for all patients enrolled in the SPIRIT IV trial for initial hospitalization and 1 year after enrollment. Cardiovascular hospitalizations, revascularization procedures, diagnostic catheterization, and dual-antiplatelet therapy costs were included. The analysis assumed equal stent costs for the Xience V and Taxus stents.

According to Abbott Vascular, the analysis showed that the Xience V's clinical benefits translated into lower overall medical costs at 1 year after the stenting procedure. The 1-year total medical costs (initial hospitalization plus follow-up) were $146 lower for Xience V versus Taxus Express². When non-target vessel revascularization costs were excluded, the 1-year medical costs were $439 lower with Xience V versus Taxus Express² (P = .02).