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Abbott Moves Forward with Bioabsorbable Stent
Positive Two Year Data Published;
Phase II of Clinical Trial to Enroll 80 Additional Patients

Abbott's bioabsorbable drug eluting stent
artist rendition of Abbott's
bioabsorbable drug eluting stent
(courtesy Abbott Vascular)

March 24, 2009 -- Abbott (NYSE: ABT) today announced that the first patient has been enrolled in phase two of the ABSORB clinical trial to assess the safety and efficacy of its novel bioabsorbable everolimus-eluting stent. Two year results of the original 30 patients were published earlier this month in The Lancet, showing reduction in plaque, zero stent thrombosis, no major cardiac events from six months to two years, successful absorption of the stent and restoration of vasomotion -- the ability of the coronary artery to contract and expand with normal pre-stent flexibility.

This next phase of the ABSORB clinical trial will enroll approximately 80 patients at 10 centers in Europe, Australia and New Zealand, and will incorporate device enhancements designed to improve deliverability and vessel support, bringing the total patient study group to 110.

Patrick W. Serruys, MD, PhD
Patrick W. Serruys, MD, PhD

Patrick W. Serruys, M.D., Ph.D., professor of interventional cardiology at the Thoraxcentre, Erasmus University Hospital, Rotterdam, and principal investigator of the ABSORB trial, summarized:

"Interventional cardiology has come a long way. It started with balloon angioplasty, which evolved into bare metal stents and then drug eluting metal stents were created. Now we have the fourth revolution in interventional cardiology technology, and patient outcomes from the first stage of ABSORB clearly show that bioabsorbable devices are the future of coronary artery disease treatment."

The recently-published two year results were critical to Abbott's progress in this area which is, as the company claims, the most advanced work yet done in bioabsorbable stents. An earlier stent, designed by Biotronik in Europe, did not fare well in outcomes against existing stents -- it is thought that the stent biodegraded too quickly and did not have time to do its work. Although some changes are being made to the next iteration of Abbott's device to give it greater radial strength, the results of the first patient cohort were very positive. As lead authors, Drs. Serruys and Ormiston, reported in The Lancet:

"30 patients with a single de-novo coronary artery lesion were followed up for 2 years clinically and with multiple imaging methods: multislice CT, angiography, intravascular ultrasound, derived morphology parameters (virtual histology, palpography, and echogenicity), and optical coherence tomography (OCT).... At 2 years after implantation the stent was bioabsorbed, had vasomotion restored and restenosis prevented, and was clinically safe, suggesting freedom from late thrombosis."

With the launch of phase two on the heels of The Lancet publication, Abbott is making clear that it believes bioabsorbable stent technology may be the next revolution in the percutaneous treatment of coronary artery disease. Not only has device technology advanced radically since angioplasty was invented 30 years ago, but the imaging technologies being used to measure success, like multislice CT angiography, intravascular ultrasound and Optical Coherence Tomography (OCT) did not exist when stents were first invented.

Some perspective on the direction of device development is discussed in this exclusive video clip (2:00), taped at the 30th Anniversary of Coronary Angioplasty in Zurich (2007) with Dr. Charles Simonton, Divisional Vice President of Medical Affairs and Chief Medical Officer for Abbott Vascular.

Dr. Simonton, who conducted the large scale Stent Registry before joining Abbott, spoke with Angioplasty.Org about the future of new devices and the potential benefits inherent in bioabsorbable stents.

It is important to note that Abbott's bioabsorbable stent is currently an investigational device and is not marketed. The company hopes to have 30 day results of the second phase of the trial by year's end. However, larger trials with more patients and more complex blockages will be needed before European can be granted -- at least 3 years away.


The following information was provided by Abbott in a press release:

The ABSORB trial is the world's first clinical trial evaluating a fully bioabsorbable drug eluting coronary stent, and advanced imaging methods were used to assess patient outcomes. As published in The Lancet, the first phase of the ABSORB trial demonstrated the following key results:
  • A zero percent rate of stent thrombosis (blood clot formation) for all patients out to two years of follow up.
  • No new major adverse cardiac events (MACE) between six months and two years. At two years, the bioabsorbable device demonstrated a MACE rate of 3.6 percent (one patient). MACE is defined as any event that resulted in re-treatment of the treated artery lesion, heart attack or cardiac death.
  • Bioabsorption of the stent at two years after implantation, as confirmed by an assessment of the stent struts using optical coherence tomography (OCT).
  • Restoration of vasomotion (ability of the blood vessel to contract and expand) was observed at two years, with the drug acetylcholine used in nine patients showing vasodilation in the previously stented area, and the drug methergin used in seven patients showing vasoconstriction in the previously stented area.
  • Reduction in plaque area in treated arteries, corresponding to an increase in blood flow between six months and two years, as confirmed by intravascular ultrasound (IVUS) and virtual histology.

Abbott is the only company with long-term clinical data evaluating the safety and performance of a bioabsorbable drug eluting coronary stent out to two years. Abbott's bioabsorbable everolimus eluting coronary device is made of polylactic acid, a proven biocompatible material that is commonly used in medical implants such as dissolvable sutures. As with a metallic stent, Abbott's bioabsorbable stent is designed to restore blood flow by propping a clogged vessel open, and to provide support until the blood vessel heals. Unlike a metallic stent, however, a bioabsorbable device is designed to be slowly metabolized by the body and completely absorbed over time.

" Abbott has consistently been at the forefront of advances in interventional cardiology -- from the early days of angioplasty to our continued success with bare metal stents and the market-leading XIENCE V drug eluting stent. Our bioabsorbable device is another example of scientific innovation leading to an interventional breakthrough," said John M. Capek, Ph.D., executive vice president, Medical Devices, Abbott. "Today's data publication in The Lancet confirms the promise our bioabsorbable device holds as a vasorestorative therapy for patients with coronary artery disease."

Reported by Burt Cohen, March 24, 2009 with additional information from Abbott Vascular