Boston Scientific's PLATINUM Workhorse Trial Presented at ACC

March 25, 2012—Boston Scientific Corporation (Natick, MA) announced 2-year follow-up data from the pivotal PLATINUM Workhorse trial evaluating the safety and effectiveness of the company's Promus Element everolimus-eluting platinum chromium (PtCr) coronary stent system compared with its Promus everolimus-eluting coronary stent system. The Promus is a private-label version of Xience V, designed and manufactured by Abbott Vascular (Santa Clara, CA) and supplied to Boston Scientific as part of a distribution agreement between the two companies.

The results were presented by Global Principal Investigator Gregg W. Stone, MD, at the American College of Cardiology annual scientific sessions in Chicago. Dr. Stone commented, “The Promus Element platinum chromium stent continues to demonstrate excellent safety and effectiveness with low rates of cardiac death, myocardial infarction, stent thrombosis, and repeat revascularization.”

According to the company, the outcomes reported at 12 months for the Promus Element and the Promus (Xience V) remained comparable at 2 years. However, an additional landmark analysis of outcomes from year 1 to year 2 demonstrated superior efficacy of the Promus Element as compared to the Promus (Xience V) device during this 12-month period of follow-up.

Dr. Stone stated, “These long-term results confirm that this device is an effective option for treating patients with coronary artery disease. Of particular note, a statistically significant reduction in recurrent ischemia requiring repeat revascularization procedures was present between the first and second year with the platinum chromium stent. This finding is potentially important, but must be confirmed by longer-term follow-up.”

In PLATINUM Workhorse trial, the investigators reported a 2-year target lesion failure (TLF) rate of 4.4% for the Promus Element stent compared to 5.8% for the Promus (Xience V) stent (P = .32). The Promus Element demonstrated numerically lower but not statistically different event rates than the Promus (Xience V) Stent in TLF components at 2 years, including cardiac death related to the target vessel (0.9% vs 1.1%; P = .98), myocardial infarction (MI) related to the target vessel (1.2% vs 2.1%; P = .28) and ischemia-driven target lesion revascularization (TLR, 2.4% vs 4%; P = .12). Low rates of target vessel revascularization (TVR, 4.2% vs 5.6%; P = .3) and stent thrombosis (ARC definite/probable, 0.5% vs 0.7%; P = .99) were observed at 2 years for both stents.

In a landmark analysis of event rates from year 1 to year 2, the Promus Element stent demonstrated statistically significant differences in TLF (1.2% vs 3%; P = .04, 56% relative reduction), and TLR (0.7% vs 2.2%; P = .02; 67% relative reduction) compared to the Promus (Xience V), showing superior efficacy of the Promus Element from 12 months to 2 years.

Trial results also confirmed a previously reported significant reduction in unplanned (bail-out or emergency) stenting with the Promus Element stent (5.9% vs 9.8%; P = .004), including a significantly lower rate of inadequate lesion coverage or “geographic miss” (1.4% vs 3.4%; P = .01). These clinical observations reflect the results of comparative bench and animal studies, which have demonstrated the enhanced visibility and deliverability of the Promus Element relative to the Promus (Xience V) stent.

According to Boston Scientific, the prospective, multicenter, randomized PLATINUM Workhorse trial enrolled 1,530 patients with up to two de novo lesions at 132 clinical sites worldwide. The trial met its primary endpoint of 12-month target lesion failure demonstrating noninferiority for the platinum chromium Promus Element stent compared to the cobalt chromium Promus (Xience V) stent.

The comprehensive PLATINUM clinical program is evaluating the safety and effectiveness of the Promus Element stent system in six multicenter studies totaling more than 1,900 patients, including single-arm studies evaluating small vessels, long lesions, pharmacokinetics, and quantitative coronary angiography and intravascular ultrasound data.

The company stated that the Promus Element stent that is used in both the Promus Element stent system and the Promus Element Plus stent system employs Boston Scientifics' PtCr alloy designed specifically for coronary stenting to provide enhanced visibility, radial strength, and conformability, with less recoil. The Promus Element Plus stent system employs an advanced low-profile delivery system to facilitate delivery of the stent across challenging lesions.

Boston Scientific received CE Mark approval for the Promus Element stent system in 2009 and approval for the Promus Element Plus stent system in 2011. In the United States, the Promus Element Plus stent system was approved by the Food and Drug Administration in 2011.