Anything to prevent the neuronal cascade of death. I would hope they take PET scans on a daily basis proving that the penumbra is not converting to dead brain.
Clinical Trials Start for Stroke Drug Developed by Scripps Research Institute, USC, and ZZ Biotech
Clinical trials start this week for a stroke drug initially created
by a team led by scientists at The Scripps Research Institute and the University of Southern California (USC), and further developed by biotech company ZZ Biotech.
The clinical trials will test the safety in humans of the
experimental drug 3K3A-APC, which has been shown in animal models to
reduce brain damage and improve motor skills after stroke when given in
conjunction with a federally approved clot-busting therapy.
“I am incredibly excited about the potential for translating our
science into a therapy that could have a significant impact on
society,” said Scripps Research Institute Professor John Griffin, who
collaborated on the scientific work with Professor Berislav V.
Zlokovic, director of the Zilkha Neurogenetic Institute at the Keck
School of Medicine of USC. “Stroke and its aftereffects are a huge
problem in this country.”
Kent Pryor, chief operating officer of ZZ Biotech, said, “We are
very pleased to have received approval from The Austrian Agency for
Health and Food Safety (AGES) to initiate our first human study with
3K3A-APC. Our extensive preclinical studies into the neuroprotective
effects of 3K3A-APC suggest that it is a promising candidate for the treatment of ischemic stroke.”
Fourth-Leading Cause of Death
Stroke, which occurs when blood flow to a part of the brain stops,
is the fourth-leading cause of death and the leading cause of adult
disability in the United States. A stroke occurs when blood flow in the
brain is interrupted, cutting off part of the brain from oxygen. Some
brain damage happens immediately, but even when blood flow is restored,
brain cells continue dying for hours or days.
According to the American Stroke Association, the Food and Drug
Administration-approved tPA (tissue plasminogen activator) is the best treatment for stroke caused by a blocked artery, but to be effective, it must be administered within three hours after symptoms start. If given outside that three-hour window, tPA has shown serious side effects in animal and human brains, including bleeding and breakdown of the brain's protective barrier.
Generally, according to the American Stroke Association, only three
to five percent of those who suffer a stroke reach the hospital and
satisfy relevant criteria in time to be considered for tPA treatment.
A New Approach
When Griffin’s hematology lab and Zlokovic’s neuroscience lab began collaborating more than a dozen years ago, activated protein C (APC) was known to stop the growth of blood clots and reduce inflammation, and was being tested for the treatment of adult severe sepsis.
By 2003, their collaborative work
pointed to a previously unsuspected ability of APC to directly prevent
programmed cell death in brain, which had emerged as a key to reducing
the effects of stroke. The team found that APC dramatically decreased
the cellular signals that convince brain cells to kill themselves after
a stroke and boosted the cellular signals that persuade the cells to
survive.
However, APC’s natural blood-thinning properties posed a potential problem to using APC as a treatment
for stroke, possibly inducing bleeding in the brain. In response to
this challenge, the Griffin lab (including Scripps Research scientists
Laurent Mosnier and Andrew Gale) produced an engineered version of APC.
“The protein normally is an anticoagulant,” Griffin explained. “We separated out the beneficial effects of the protein acting on cells from this anticoagulant activity. This was done by protein
engineering of the 3K3-APC variant to lose most of its anticoagulant
activity while retaining its direct actions on cell signaling.”
Promising Data
Further work from the team on the engineered 3K3A-APC lent support
to the decision to proceed with clinical trials. Large-scale production
of this biologic drug, 3K3A-APC, was accomplished by ZZ Biotech with
the guidance of Griffin and Thomas Davis, who is a distinguished
professor of pharmacology at the University of Arizona.
The journal Stroke published a paper by Zlokovic, Griffin,
and colleagues online ahead of print on July 17, 2012
(doi:10.1161/strokeaha.112.658997), showing the results of giving the
federally approved stroke treatment tPA—alone and in combination with 3K3A-APC—to mice and rats four hours after onset of ischemic stroke.
The team also gave 3K3A-APC for three consecutive days after stroke
and measured the amount of brain damage, bleeding, and motor ability of
the rodents up to seven days afterward.
The researchers found that, under those conditions, tPA therapy
alone caused bleeding in the brain and did not reduce brain damage or
improve motor ability when compared to the control. The combination of
tPA and 3K3A-APC, however, reduced brain damage by more than half,
eliminated tPA-induced bleeding, and significantly improved motor
ability.
“We have developed something that not only counteracts the bleeding,
but also reduces brain damage and significantly improves behavior
after stroke,” said Zlokovic. “I feel very strongly that this approach
will extend the therapeutic window for tPA."
The Next Step
The stage is now set for ZZ Biotech, founded by Zlokovic with USC
benefactor Selim Zilkha, to launch the first clinical trials in humans
for 3K3A-APC under the supervision of a leading stroke trialist,
Professor Patrick Lyden, chair of the Department of Neurology at
Cedars-Sinai Medical Center, Los Angeles.
The new Phase 1 study is a randomized, double-blind,
placebo-controlled, single-center trial that will investigate the
safety and pharmacokinetics of single and multiple ascending doses of
3K3A-APC in healthy adult volunteers. Approximately 62 eligible adult
subjects will be assigned sequentially to 1 of 10 cohorts, at
successively higher single doses, followed by successively higher
multiple doses. Results of the study are anticipated in the first
quarter of 2013.
“We are excited by the prospect of one day putting 3K3A-APC in
doctors’ hands to help reduce the tremendous suffering caused by
stroke,” said Joseph Romano, chief executive officer of ZZ Biotech.
About The Scripps Research Institute
The Scripps Research Institute is one of the world's largest
independent, not-for-profit organizations focusing on research in the
biomedical sciences. Over the past decades, Scripps Research has
developed a lengthy track record of major contributions to science and
health, including laying the foundation for new treatments for cancer, rheumatoid arthritis,
hemophilia, and other diseases. The institute employs about 3,000
people on its campuses in La Jolla, CA, and Jupiter, FL, where its
renowned scientists—including three Nobel laureates—work toward their
next discoveries. The institute's graduate program, which awards Ph.D.
degrees in biology and chemistry, ranks among the top ten of its kind
in the nation. For more information, see www.scripps.edu.
ZZ Biotech, LLC
ZZ Biotech is a company headquartered in Houston, TX with a mission to develop innovative biological treatments
for the aging and damaged brain, including those affected by stroke
and other neurodegenerative disorders. ZZ Biotech is developing a
genetically engineered variant of recombinant human wild-type activated
protein C (APC), named 3K3A-APC, that has reduced anticoagulant
activity, but preserved cell-protective and anti-inflammatory
activities compared to APC. ZZ Biotech is studying the safety and
pharmacokinetics of 3K3A-APC in healthy human volunteers in an ongoing
Phase 1 clinical study.
If doctors feel protected from being sued for causing bleeding with tPA they might be more willing to intervene more often in the ER. I hope this research pans out.
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