Ian T Meredith, director MonashHeart, Monash Medical Centre, Melbourne, Australia, presented results from the EVOLVE first in-human use trial of the Synergy everolimus-eluting stent system (Boston Scientific) compared to the Promus Element everolimus-eluting stent system (Boston Scientific) in treating de novo coronary artery lesions at the 23rd annual Transcatheter Cardiovascular Therapeutics (TCT) scientific symposium in San Francisco, USA.
The trial provided 30-day clinical and six-month angiographic primary endpoint data evaluating the safety and effectiveness of the bioabsorbable polymer-coated Synergy stent.
The prospective, randomised, single-blind, non-inferiority trial enrolled 291 patients at 29 sites in Europe, Australia and New Zealand. Patients were randomised to either one of two dose formulations of everolimus used on the Synergy stent, which employs an ultra-thin abluminal bioabsorbable polymer, or to the commercially available Promus Element stent, which employs the everolimus drug and a permanent durable polymer. One formulation of the Synergy stent used an everolimus dose and release profile similar to the Promus Element stent, while the second formulation of the Synergy stent used a similar release profile but half the dose of everolimus.
“The Synergy stent met the primary non-inferiority endpoint of six-month late loss compared to the Promus Element stent, demonstrating effectiveness of drug elution from this abluminal bioabsorbable polymer,” said Meredith, principal investigator of the trial. “The platform also appears to be safe with very low rates of myocardial infarction and revascularisation and no reported cardiac deaths or stent thrombosis. The Synergy stent is designed to address potential limitations with durable polymer coatings used on currently available drug-eluting stents, which may be associated with chronic inflammation and impaired healing. The impressive clinical and angiographic results from EVOLVE bode well for this innovative new coronary stent technology.”
The primary angiographic endpoint of independently adjudicated mean late loss at six months was 0.10 mm for the Synergy stent and 0.13 mm for the half-dose Synergy stent, compared with 0.15 mm for the Promus Element stent (p<0.001 for the non-inferiority comparison for both Synergy doses versus Promus Element). Additional six-month angiographic outcomes for diameter stenosis and binary restenosis showed no statistical differences between both stents.
The trial met the primary clinical endpoint of target lesion failure at 30 days, defined as target-vessel-related cardiac death, target-vessel-related myocardial infarction or ischaemia-driven target lesion revascularisation. At 30 days, target lesion failure in both Synergy stent arms was not statistically different from the Promus Element stent (1.1% for the Synergy stent versus 0.0% for the Promus Element stent, p=0.49 for superiority comparison, and 3.1% for the half-dose Synergy stent, p=0.12 for superiority comparison with the Promus Element stent). Target lesion failure continued to show no significant differences among the three stent groups out to six months with rates of 2.2% for the Synergy stent versus 3.1% for the Promus Element stent (p=1.00) and 4.1% for the half-dose Synergy stent (p=0.72 versus the Promus Element stent). Clinical follow-up at six months demonstrated no events for cardiac death, Q-wave myocardial infarction and stent thrombosis. Myocardial infarction was 1.1% for the Synergy stent, 0.0% for the Promus Element stent (p=0.49) and 3.1% for the half-dose Synergy stent (p=0.25), all presenting as Non-Q-wave myocardial infarction.
The Synergy stent features the same proprietary platinum chromium alloy and similar stent design used in the Promus Element stent to enable thinner struts, increased conformability, deliverability and flexibility while reducing recoil and improving visibility.
“Our fourth-generation Synergy stent is designed to offer the performance advantages of our innovative platinum chromium platform while significantly reducing the amount of polymer and drug to which the vessel wall is exposed,” said Keith D Dawkins, senior vice president and chief medical officer at Boston Scientific’s Cardiology, Rhythm and Vascular Group. “EVOLVE trial data will be used to support CE mark approval for Synergy, while additional larger studies are planned to further assess clinical event rates and the potential for reduced dual antiplatelet therapy with this novel stent technology.”
In the USA, the Synergy stent and the Promus Element stent are investigational devices, limited by applicable law to investigational use only and not available for sale.