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Early and Rapid Cooling Following Heart Attack May Reduce Damage to Cardiac Muscle
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April 15, 2008, San Diego --
Cardium Therapeutics (Amex: CXM) and its operating unit InnerCool Therapies announced today that positive findings from a preclinical study, demonstrating a new and expanded benefit of early rapid hyperthermia (cooling) for the potential treatment of acute myocardial infarction (heart attack), has been published online by BioMed Central (BMC) Cardiovascular Disorders (2008, 8:7, April 10, 2008).
The study, conducted by a team of interventional
cardiologists at the Lund University Hospital, Sweden, evaluated
the effect of early and rapid cooling induced by a combination
of cold saline infusion along with InnerCool's endovascular
Celsius Control™ System, before or immediately after reperfusion
when coronary blood flow was restored in the heart in a porcine
heart attack model.
Results from this study demonstrated
that rapid cooling (to ‹35 degrees Celsius) prior to reperfusion
significantly reduced overall myocardial infarct size (a measure
of tissue damage in the heart) and protected the heart from
other injury.

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"We believe that InnerCool's
low-profile, high-performance endovascular cooling system
has the capacity to achieve rapid cooling within the short
time available before coronary reperfusion must occur in
order to potentially limit the amount of damage due to reperfusion
injury following heart attack," stated Christopher J. Reinhard,
Chairman and Chief Executive Officer of Cardium Therapeutics
and InnerCool Therapies. "To achieve cooling rates that were
shown in the study to be beneficial requires the ability
to lower core body temperature to 35 degrees Celsius or less
within a time window as short as about 15 minutes while patients
are awake. InnerCool's Accutrol catheter not only provides
rapid cooling but the unique integrated temperature sensor
enables fast and precise feedback of core body temperature,
compared to delayed temperature feedback using peripheral
temperature probes. Speed and precision are performance features
that can be especially critical in acute care settings such
as those following a heart attack." |
Rapid & Early Cooling Heart Attack
Preclinical Study Results
This study was designed to further investigate the therapeutic
potential of early and rapid hypothermia to preserve heart tissue
following a heart attack. Using a closed-chest porcine heart attack
model in which the coronary artery supplying the heart muscle was
initially blocked and later reopened, as occurs in patients after
a heart attack or acute myocardial infarction (MI), the investigators
evaluated the effects of rapid cooling to a target temperature
of 33 degrees Celsius to 35 degrees Celsius on myocardial infarct
size as assessed by cardiac magnetic resonance imaging (MRI). Rapid
hypothermia, induced by the infusion of one liter of cold saline
in combination with InnerCool's endovascular catheter-based temperature
modulation system, initiated either prior to or after restoration
of blood flow (reperfusion), was compared to a normal core body
temperature of 38 degrees Celsius throughout the procedure.
The data showed that early rapid cooling substantially reduced
the damage to heart muscle that typically follows a heart attack
and reperfusion. In particular, cooling prior to reperfusion reduced
overall myocardial infarct size by 43% compared to hypothermia
after reperfusion (p‹0.05), and by 39% compared to normothermia (p‹0.05).
In addition, hypothermia initiated either before or after reperfusion
also significantly reduced impairment of blood flow in the coronary
microvasculature (microvascular obstruction) that may be associated
with reperfusion injury.
The results from this study are consistent with clinical findings
from the Intravascular Cooling Adjunctive to Percutaneous Coronary
Intervention (ICE-IT) study, a 228 patient study sponsored by InnerCool,
in which infarct size was reduced (43% in anterior MIs and 39%
in inferior MIs) in patients who were cooled rapidly to ‹35
degrees Celsius prior to reperfusion with an endovascular temperature
modulation system as an adjunct to angioplasty and stent procedures.
The current study further confirms this correlation between rapid
cooling to a body core temperature of less than 35 degrees Celsius
prior to reperfusion and reduction in infarct size.
" Preclinical and preliminary clinical data suggest that rapid patient cooling using intravenous cold saline in combination with endovascular hypothermia can be initiated without causing delay of reperfusion therapy and may have the potential to enable interventional cardiologists to dramatically reduce heart tissue damage following a heart attack," stated
David Erlinge, M.D., Ph.D. of the Lund University Cardiology Center.
New Clinical Heart Attack Study Underway
Based on these findings, InnerCool is sponsoring a study on the
use of early and rapid cooling of patients with myocardial infarction
(MI or heart attack), which is being co-sponsored and conducted
by the interventional cardiology center at Lund University Hospital,
Sweden. The ongoing clinical study, called RAPID MI-ICE (Rapid
Intravascular Cooling in Myocardial Infarction as Adjunctive to
Percutaneous Coronary Intervention), is expected to enroll approximately
20 patients who present within six hours of their heart attack
and require angioplasty and stent procedures in order to restore
blood flow to the heart. Eligible patients will be randomized to
one of two treatment protocols, and the effects on heart tissue
damage will be compared. Patients randomized to the cooling arm
(hypothermia) will be infused with 1 liter of iced saline in addition
to endovascular cooling with the InnerCool Accutrol™ catheter,
which contains an integrated temperature sensor that accurately
measures the patient's core body temperature. Patients assigned
to the normothermia arm will receive routine standard of care without
induced hypothermia. The trial will employ cardiac MRI to provide
an assessment of the damage to the heart, as measured by infarct
size, within days of the heart attack. Additional details of the
study can be found at http://www.clinicaltrials.gov.
Myocardial Reperfusion Injury
The American Heart Association estimates that the annual incidence
of myocardial infarction (MI) is 600,000 new attacks and 320,000
recurrent attacks. After an acute myocardial infarction, early
and successful myocardial reperfusion with the use of thrombolytic
therapy such as tissue plasminogen activator (tPA) or primary percutaneous
coronary intervention (PCI) is the most effective strategy for
reducing the size of a myocardial infarct and other complications
to lead to improved clinical outcome. Reperfusion, the process
of restoring blood flow to the ischemic myocardium, can itself
lead to additional injury beyond that caused by ischemia due to
coronary blockage. This phenomenon, termed myocardial reperfusion
injury, can reduce the beneficial effects of myocardial reperfusion.
Preclinical studies in models of acute myocardial infarction suggest
that reperfusion injury accounts for up to 50% of the final infarct
size.
Reperfusion injury refers to damage to tissue caused when blood
supply returns to the tissue after a period of ischemia such as
during blockage of the coronary arteries. The temporary absence
of oxygen and nutrients from blood creates a condition in which
the restoration of blood flow results in inflammation and damage
through the induction of oxidative stress, caused by the production
of reactive oxygen species. Reperfusion injury is due in part to
the inflammatory response of damaged tissues. White blood cells
carried to the area by the newly returning blood release a variety
of inflammatory factors in response to tissue damage. The restored
blood flow reintroduces oxygen within cells that damages cellular
proteins, DNA, and the cell's plasma membrane. Damage to the cell's
membrane may in turn cause the release of more inflammatory substances
that may turn on apoptosis, or programmed cell death, involving
a series of biochemical events that lead to a variety of cellular
changes, including cell shrinkage, chromatin condensation, and
chromosomal DNA fragmentation. White blood cells may also build
up in small capillaries, obstructing them and leading to more ischemia.
In its most extreme, myocardial reperfusion injury can result in
the death of cardiac tissue that was viable immediately before
the restoration of blood flow and, as a consequence, increased
myocardial infarct size. Reperfusion injury is associated with
adverse clinical outcomes after a heart attack and may contribute
to patient mortality despite successful reperfusion.
About Patient Temperature Modulation
Patient temperature modulation is a rapidly-advancing field focused
on preserving ischemic tissue and improving patient outcomes following
major medical events such as cardiac arrest, heart attack and stroke,
as well as in the management of patients experiencing trauma or
fever. Temperature modulation is intended to cool patients in order
to reduce cell death and damage caused by ischemic events in which
blood flow to critical organs such as the heart or brain is restricted,
and to prevent or reduce associated injuries such as tissue damage
following a heart attack or adverse neurologic outcomes.
Numerous scientific and medical articles have described the usefulness
of temperature modulation, such as induced hypothermia (cooling),
which is designed to protect endangered cells, prevent tissue death
and preserve organ function following acute events associated with
severe oxygen deprivation such as cardiac arrest or stroke. Therapeutic
hypothermia is believed to work by protecting critical tissues
and organs (such as the heart, brain, and kidneys) following ischemic
or inflammatory events, by lowering metabolism and preserving cellular
energy stores, thereby potentially stabilizing cellular structure
and preventing or reducing injuries at the cellular, tissue and
organ level. Two international clinical trials on hypothermia after
cardiac arrest published in The New England Journal of Medicine
demonstrated that induced hypothermia reduced mortality and improved
long-term neurological function. Based on these and other results,
the American Heart Association (AHA) and the International Liaison
Committee on Resuscitation (ILCOR) have issued guidelines recommending
that cardiac arrest victims be treated with induced hypothermia.
Ischemic diseases constitute the largest segment of the medical
market in the United States and in almost all developed countries
worldwide. For example, in the U.S. and other developed countries,
an estimated 1.4 million people experience cardiac arrest each
year, of which an increasing number (currently about 350,000) survive
to receive advanced care. The AHA guidelines now recommend the
use of therapeutic cooling as part of the critical care procedures
for patients with an out-of-hospital cardiac arrest following ventricular
fibrillation. With respect to heart attacks, an estimated 325,000
people in the U.S., and approximately 375,000 people outside the
U.S., receive emergency angioplasty or anti-clotting treatment
as first-line care.
In the area of stroke, approximately 700,000 Americans experience
a stroke each year, and a comparable number of patients are affected
outside the U.S. Although tissue plasminogen activator (tPA) has
been shown to lessen damage associated with a stroke, particularly
if it can be administered within three hours of onset, many stroke
patients continue to suffer advanced neurologic damage even though
they have received tPA. More importantly, most stroke victims do
not arrive at the hospital in time to be candidates for tPA. The
American Stroke Association (ASA) has now identified the use of
therapeutic hypothermia as a promising area of research for the
potential treatment of stroke victims, and it is the subject of
ongoing clinical studies being sponsored by InnerCool Therapies
and supported by the U.S. National Institutes of Health.
About InnerCool
InnerCool Therapies, Inc., a subsidiary of Cardium Therapeutics,
Inc., is a San Diego-based medical technology company in the emerging
field of patient temperature modulation, which is designed to rapidly
and controllably cool the body in order to reduce cell death and
damage following acute ischemic events such as cardiac arrest or
stroke, and to potentially lessen or prevent associated injuries
such as adverse neurological outcomes. InnerCool is believed to
be the only company developing, marketing and selling both cost-effective
surface and high-performance endovascular patient temperature systems,
providing a range of patient-appropriate solutions for hospital
and medical centers. For more information about InnerCool and patient
temperature modulation, please visit http://www.innercool.com.
InnerCool's high-performance endovascular approach to patient temperature
modulation is based on a single-use flexible metallic catheter
and a fully- integrated cooling system, which allows for rapid
and controlled cooling and re-warming. InnerCool's endovascular
system integrates a number of desirable features including a slim
catheter profile, a highly efficient flexible metallic thermal
transfer element, a built-in temperature monitoring sensor, and
a programmable console capable of rapidly and controllably inducing,
maintaining and reversing therapeutic cooling. InnerCool's endovascular
catheter-based Celsius Control System™ has received FDA 510(k)
clearance for use in inducing, maintaining and reversing mild hypothermia
in neurosurgical patients, both in surgery and in recovery or intensive
care. The system has also received FDA clearance for use in cardiac
patients in order to achieve or maintain normal body temperatures
during surgery and in recovery / intensive care, and as an adjunctive
treatment for fever control in patients with cerebral infarction
and intracerebral hemorrhage. Potential additional applications
of the technology include endovascular cooling for cardiac arrest,
acute ischemic stroke and myocardial infarction (heart attack).
InnerCool's next-generation RapidBlue™ system for high-performance
endovascular temperature modulation is expected to receive FDA
clearance in the second quarter 2008, and to initially have the
same clearance as the Celsius Control System. The RapidBlue system
includes a programmable console with an enhanced user interface
and a catheter designed to quickly modulate patient temperature
in association with surgery or other medical procedures. The RapidBlue
system powers InnerCool's Accutrol™ catheter, which has a flexible
metallic temperature control element and a built-in temperature
feedback sensor to provide fast and precise patient temperature
control.
InnerCool's CoolBlue surface temperature modulation system, which
includes a console and a disposable CoolBlue™ vest with upper thigh
pads, is designed to provide a complementary tool for use in less
acute patients or in clinical settings best suited to prolonged
temperature management. InnerCool's CoolBlue vest and thigh pads
wrap the body without requiring any adhesives to stick to the skin
and produce cooling rates of around 1 degree Celsius per hour,
i.e. similar to those of currently-marketed surface cooling systems
and endovascular systems using inflatable balloon-based catheters.
InnerCool's CoolBlue external or surface-based temperature modulation
system is designed to cool or warm patients from outside of their
bodies and is intended for use in less acute settings such as in-hospital
fever management.
About Cardium
Cardium Therapeutics, Inc. and its subsidiaries, InnerCool Therapies,
Inc. and the Tissue Repair Company, are medical technology companies
primarily focused on the development, manufacture and sale of innovative
therapeutic products and devices for cardiovascular, ischemic and
related indications. Cardium's lead product candidate, Generx™
(alferminogene tadenovec, Ad5FGF4), is a DNA-based growth factor
therapeutic being developed for potential use by interventional
cardiologists as a one-time treatment to promote and stimulate
the growth of collateral circulation in the hearts of patients
with ischemic conditions such as recurrent angina. For more information
about Cardium and its businesses, products and therapeutic candidates,
please visit http://www.cardiumthx.com or view its 2006 Annual
Report at http://www.cardiumthx.com/flash/pdf/2006CardiumAnnualReport.pdf.
Cardium's InnerCool Therapies subsidiary is a San Diego-based medical
technology company in the emerging field of patient temperature
modulation therapy to rapidly and controllably cool the body in
order to reduce cell death and damage following acute ischemic
events such as cardiac arrest or stroke, and to potentially lessen
or prevent associated injuries such as adverse neurological outcomes.
For more information about Cardium's InnerCool subsidiary and patient
temperature modulation, including InnerCool's Celsius Control System™,
which has received regulatory clearance in the U.S., Europe and
Australia, please visit http://www.innercool.com.
Cardium's Tissue Repair Company subsidiary (TRC) is a San Diego-based
biopharmaceutical company focused on the development of growth
factor therapeutics for the treatment of severe chronic diabetic
wounds. TRC's lead product candidate, Excellarate™, is a DNA-activated
collagen gel for topical treatment formulated with an adenovector
delivery carrier encoding human platelet-derived growth factor-BB
(PDGF-BB). Excellarate is initially being developed to be administered
once or twice for the potential treatment of non-healing diabetic
foot ulcers. Other potential applications for TRC's Gene Activated
Matrix™ (GAM™) technology include therapeutic angiogenesis (cardiovascular
ischemia, peripheral arterial disease) and orthopedic products,
including hard tissue (bone) and soft tissue (ligament, tendon,
cartilage) repair. For more information about Cardium's Tissue
Repair Company subsidiary, please visit http://www.t-r-co.com.
Forward-Looking Statements
Except for statements of historical fact, the matters discussed
in this press release are forward looking and reflect numerous
assumptions and involve a variety of risks and uncertainties, many
of which are beyond our control and may cause actual results to
differ materially from stated expectations. For example, there
can be no assurance that results observed in animal models of disease
will be predictive of results in humans, that product modifications
or launches will be successful or that the resulting products will
be favorably received in the marketplace, that our products or
proposed products will prove to be sufficiently safe and effective,
that our products or product candidates will not be unfavorably
compared to competitive products that may be regarded as safer,
more effective, easier to use or less expensive, that results or
trends observed in one clinical study will be reproduced in subsequent
studies, that third parties on whom we depend will behave as anticipated,
that necessary regulatory approvals will be obtained. Actual results
may also differ substantially from those described in or contemplated
by this press release due to risks and uncertainties that exist
in our operations and business environment, including, without
limitation, our limited experience in the development, testing
and marketing of therapeutic hypothermia devices and whether our
efforts to launch new devices and systems will be successful or
completed within the time frames contemplated, risks and uncertainties
that are inherent in the conduct of human clinical trials, including
the timing, costs and outcomes of such trials, our dependence upon
proprietary technology, our history of operating losses and accumulated
deficits, our reliance on collaborative relationships and critical
personnel, and current and future competition, as well as other
risks described from time to time in filings we make with the Securities
and Exchange Commission. We undertake no obligation to release
publicly the results of any revisions to these forward-looking
statements to reflect events or circumstances arising after the
date hereof.
Cardium Therapeutics™ and Generx™ are trademarks of Cardium
Therapeutics,
Inc.
Gene Activated Matrix™, GAM™ and Excellarate™ are trademarks of Tissue Repair
Company.
InnerCool Therapies®, InnerCool®, Celsius Control System™,
RapidBlue™, CoolBlue™ and Accutrol™ are trademarks of InnerCool Therapies, Inc.
Source: Cardium Therapeutics,
Inc.
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