The 2-year reductions in stent thrombosis reported from the COMPARE trial were even more striking, discussants said at the meeting.
In this trial, 1,800 consecutive patients undergoing PCI at one center in Rotterdam, the Netherlands, were randomly assigned in 1:1 fashion to treatment with the Xience V stent or the Taxus Liberté stent, a second-generation paclitaxel-eluting stent.
(The Taxus Express stent used in SPIRIT IV is no longer commercially available, according to a spokesperson for Boston Scientific. The Taxus Liberté stent, which uses the same polymer but a different stent platform, is currently available in the United States and in Europe, he said.)
The rate of definite/probable stent thrombosis (again, by ARC definition) at 2 years in the COMPARE trial was 0.9% in the Xience V group and 3.9% in the Taxus group – higher rates than found in SPIRIT IV. Most notable, however, was a 77% reduction in very late definite/probable stent thrombosis in the Xience V arm. The rate of this outcome was 0.3% in the Xience V group and 1.5% in the Taxus Liberté group, reported Dr. Peter Smits of Maasstad Ziekenhuis.
This difference is especially notable because the vast majority of patients were no longer taking dual antiplatelet therapy at 2 years, said Dr. Smits, principal investigator of COMPARE. In contrast, more than 70% of patients in each arm of the SPIRIT IV trial remained on dual antiplatelet therapy at 2 years.
Unlike the SPIRIT design, the COMPARE trial was designed to be an “all-comer, real-world study” without exclusions for complex patients. At 2 years, the superiority of the Xience V stent for the primary end point – a composite of all mortality, nonfatal MI, and target vessel revascularization (MACE) – was maintained, with larger absolute differences between the stents than at 12 months.
At 1 year, this primary end point had occurred in 6.2% and 9.1% in the Xience V and Taxus groups, respectively, for an absolute difference of 2.9%. At 2 years, these rates rose to 9.0% and 13.7%, for an absolute difference of 4.7%. There were similar reductions in secondary end points. As in SPIRIT IV, there were no benefits of the Xience V stent for diabetic patients.
Both studies are still ongoing and will conclude with 5-year analyses.
The lack of benefit of the Xience V stent in diabetics means there is a difference in their mechanistic response.
Source DR. STONE