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, 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
