Abbott, a global based health care company, has reported positive long-term data from the two-stage ABSORB trial, which is evaluating the ABSORB drug eluting bioresorbable vascular scaffold (BVS) for the treatment of coronary artery disease. Five-year results from the first stage and two-year and 18-month data from the second stage of the ABSORB trial were recently presented at the 2011 American Heart Association's Scientific Sessions in Orlando and the 23rd Annual Transcatheter Cardiovascular Therapeutics (TCT) scientific symposium in San Francisco.
At five years, there were no reports of cardiac deaths, blood clots (thromboses) or ischemia-driven target lesion revascularization in the first stage of the ABSORB trial, which enrolled 30 patients. The major adverse cardiac event (MACE) rate at five years was 3.4 per cent, with no new events reported between six months and five years.
At two years, no blood clots and a MACE rate of 6.8 per cent were reported in 44 patients from the second stage of the ABSORB trial. Imaging data at two years showed a low late loss of 0.27 mm, which is comparable to the one-year result. Of the patients' vessels that were assessed for vasomotor function at two years, the majority showed signs of vasomotion (constriction or dilation of the vessel), indicating that vessel movement was observed in the arteries of these patients as their vessels were not constrained by a permanent metallic implant.
“These outcomes suggest that a temporary scaffold like ABSORB provides durable results over the long term and a permanent implant may not be necessary to effectively treat patients with coronary artery disease,” said Patrick W Serruys, MD, PhD, professor of interventional cardiology at the Thoraxcentre, Erasmus University Hospital, Rotterdam, the Netherlands and primary investigator for the ABSORB clinical trial. “The clinical results suggest that this innovative therapy could provide long-term benefits for patients with coronary artery disease.”
Additionally, 18-month data from 101 patients enrolled in the second stage of the ABSORB trial were presented. The results were consistent with what have been reported to date in the ABSORB trial: no cases of cardiac death or blood clots and a MACE rate of 8.0 per cent.
“It is encouraging to see that the safety and efficacy data we've seen for ABSORB continue to be strong over the long term and support the earlier results from this trial,” said Charles A Simonton, MD, FACC, FSCAI, divisional vice president, Medical Affairs, and chief medical officer, Abbott Vascular. “We look forward to conducting a number of additional clinical trials for ABSORB around the world in 2012 in an effort to further build the body of clinical evidence supporting this device.”
ABSORB is made of polylactide, a proven biocompatible material that is commonly used in medical implants such as dissolvable sutures. Studies to date have shown that the ABSORB device restores blood flow by opening a blocked vessel and providing support to the vessel until the device dissolves after approximately two years. Because a permanent metallic implant is not left behind, naturally occurring vessel functions may be restored, which is one of the features that makes this device a significant advancement. In January 2011, Abbott announced that ABSORB received CE Mark and is authorized for sale in Europe for the treatment of coronary artery disease. ABSORB currently is under development and is not available for sale in the United States.
Abbott's BVS delivers everolimus, an anti-proliferative drug. Everolimus is developed by Novartis Pharma AG and is licensed to Abbott by Novartis for use on its drug eluting vascular devices. Everolimus has been shown to inhibit treated-site neointimal growth in the coronary vessels following vascular device implantations, due to its anti-proliferative properties.
The ABSORB trial is the first clinical trial evaluating a drug eluting BVS for the treatment of coronary artery disease. Abbott is the only company with five-year clinical data on a complete patient set evaluating the safety and performance of this technology. The ABSORB trial is a prospective, non-randomized (open label), two-stage study that enrolled 131 patients from Australia, Belgium, Denmark, France, the Netherlands, New Zealand, Poland and Switzerland. Key endpoints of the study include assessments of safety – MACE and treated-site thrombosis rates – at 30 days and at six, nine, 12 and 24 months, with additional annual clinical follow-up for up to five years, as well as an assessment of the acute performance of the device.
Other key endpoints of the study include imaging assessments by angiography, intravascular ultrasound (IVUS), optical coherence tomography (OCT), and other imaging modalities at six, 12, 18, 24, 36 and 60 months.