November 11, 2011 – Biosensors International Group announced two-year results from the BioFreedom first-in-human trial, which showed similar clinical outcomes between BioFreedom, a polymer-free, drug-coated stent (DCS), and Boston Scientific’s Taxus Liberté drug-eluting stent (DES). There was no evidence of stent thrombosis in either trial arm. Results were presented by Professor Eberhard Grube, University Hospital Bonn, Germany, at the 23rd annual Transcatheter Cardiovascular Therapeutics (TCT) scientific symposium, sponsored by the Cardiovascular Research Foundation.
BioFreedom represents the latest development in Biosensors’ stent technology, featuring a micro-structured abluminal surface which permits the controlled release of Biolimus A9 (BA9) without the use of a polymer. BA9 is a highly lipophilic antirestenotic drug developed by Biosensors specifically for use with stents. Two versions of the stent were studied in this trial: one with a drug dosage of 15.6 µg/ per mm of stent length (standard dose) –– the same as that used in BioMatrix Flex –– and the other with a drug dosage of 7.8 µg/ per mm of stent length (low dose).
182 patients were equally randomized into three treatment groups: BioFreedom standard dose (SD); BioFreedom low dose (LD); and Taxus Liberté. Ninety-nine percent of enrolled patients were followed up at two years.
The rate of MACE (major adverse cardiac events, including a composite of all death, MI, emergent cardiac artery bypass graft [CABG] and target lesion revascularization [TLR]) observed in patients treated with BioFreedom SD was numerically lower than that observed in patients treated with Taxus Liberté (6.8% vs. 10.0%: p=0.54). TLR was performed half as often on patients treated with BioFreedom SD as those treated with Taxus Liberté (3.4% vs. 6.7% p=0.42).
Both BioFreedom SD and BioFreedom LD demonstrated sustained safety up to two years, including absence of stent thrombosis.
“The results from this study are very significant, as they demonstrate that a polymer-free drug-coated stent is as safe and efficacious as a conventional drug-eluting stent with a durable polymer coating over a two-year period,” said Professor Grube. “I am excited about the concept of a polymer-free stent, as the rapid drug clearance and absence of a polymer drug carrier could promote more rapid vessel healing and ultimately reduce the need for longer term dual anti-platelet therapy. A larger study is now required to confirm these encouraging findings.”
BioFreedom FIM is a prospective, multi-center study involving 182 patients with symptomatic ischemic heart disease. It involves a first cohort of 75 patients, evaluated for in-stent late lumen loss at four months, and a second cohort of 107 patients, evaluated at 12 months. The primary endpoint of BioFreedom FIM was in-stent late lumen loss at 12 months in the second cohort. Results from the first cohort, showing four-month non-inferiority of late lumen loss between BioFreedom and Taxus Liberté, were presented at TCT in 2009. Twelve-month data from the second cohort was presented at TCT in 2010, in which BioFreedom SD demonstrated similar efficacy, measured by late lumen loss, compared with Taxus Liberté (p non-inferiority = 0.001), with a trend towards superiority (psup = 0.11).
The clinical status of the patients in the trial is being followed up out to five years and reported annually.
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