Dr. Dennis Morrison poses with the Microencapsulation Electrostatic
Processing System flight hardware that was used on the International
Space Station to produce microcapsules for cancer treatment delivery. Credit: Image courtesy of NASA
Invasive and systemic cancer treatment is a necessary evil for many
people with the devastating diagnosis. These patients endure therapies
with ravaging side effects, including nausea, immune suppression, hair
loss and even organ failure, in hopes of eradicating cancerous tissues
in the body. If treatments targeted a patient's cancerous tissues, it
could provide clinicians with an alternative to lessen the delivery of
toxic levels of chemotherapy or radiation. Imagine the quality of life
from such therapies for patients. Remarkably, research that began in
space may soon result in such options here on Earth. As we recognize February as National Cancer Prevention Month, it is
useful to also point out the continuous improvements to cancer treatment
through research and discovery. Using the distinctive microgravity
environment aboard the International Space Station, a particular series
of research investigations is making further advancements in cancer
therapy. A process investigated aboard the space station known as
microencapsulation is able to more effectively produce tiny,
liquid-filled, biodegradable micro-balloons containing specific
combinations of concentrated anti-tumor drugs. Using specialized
needles, doctors can deliver these micro-balloons, or microcapsules, to
specific treatment sites within a cancer patient. This kind of targeted
therapy may soon revolutionize cancer treatment delivery.
Use of the microgravity environment aboard the space station for
microencapsulation experiments was a necessity before the ability to
develop an Earth-based technology for making these microcapsules. "The
technique that we have for making these microcapsules could not be done
on the ground, because the different densities of the liquids would
layer," explained Dennis Morrison, Ph.D., retired NASA principal
investigator of the Microencapsulation Electrostatic Processing
System-II (MEPS-II) study and current vice president and director for
microencapsulation research and development at NuVue Therapeutics, Inc.
"But in space, since there is not sedimentation due to gravity,
everything goes spherical."
The MEPS operations in microgravity
brought together two liquids incapable of mixing on Earth (80 percent
water and 20 percent oil) in such a way that spontaneously caused
liquid-filled microcapsules to form as spherical, tiny, liquid-filled
bubbles surrounded by a thin, semipermeable outer membrane.
In
space, surface tension shapes liquids into spheres. Each molecule on a
liquid's surface is pulled with equal tension by its neighbors. The
closely integrated molecules form into the smallest possible area, which
is a sphere. In effect, the MEPS-II system allowed a combination of
liquids in a bubble shape because surface tension forces took over and
allowed the fluids to interface rather than sit atop one another.
"We
were able to figure out what parameters we needed to control so we
could make the same kind of microcapsules on the ground," said Morrison.
"Now, we no longer have to go to space. Space was our teacher, our
classroom to figure out how we could make these on Earth."
Though
the MEPS-II technology was produced on the space station in 2002, the
ensuing global economic struggles and funding hurdles made it difficult
to raise investor capital for new clinical trials of the microcapsules
in humans. This gap in the research slowed movement from discovery to an
actual product that improves human health.
The MEPS-II system is
now being brought to commercial scale under U.S. Food and Drug
Administration (FDA) Good Manufacturing Practice requirements by NuVue.
NuVue exclusively licensed the MEPS technology for medical uses,
including the treatment of cancer. These cancer therapies are now the
subject of several patents and patent pending applications.
Commercialization
of the MEPS technology and methods to develop new applications for
these unique microcapsules has already begun. The space station research
led to 13 licensed microcapsule-related patents and two that are
pending. In addition, NuVue has designed devices integrating the
delivery of the MEPS-II microcapsules with enhanced ultrasound
visualization and cryotherapeutic effects, which are the subject of four additional issued and three pending patents.
NuVue
also is currently seeking FDA approval of MEPS microcapsules containing
pharmaceuticals and marker imaging agents to view MEPS microcapsules
during ultrasound. Fortunately, the MEPS microcapsules were made in NASA
labs for the space station under stringent conditions comparable to
those of existing FDA requirements.
Through the use of NuVue's
specialized biopsy needles working in concert with their enhanced
ultrasound guided visualization technology, the needles are visible by
an ultrasound imaging system. This allows for a targeted and
site-specific approach of the MEPS microencapsulated drug delivery to
the tumor. With this targeted approach, the MEPS microcapsules reduce
the amount of unpleasant side effects of chemotherapy, whereas normal
chemotherapy involves pharmaceutical injection into the entire body to
treat cancer cells present in a patient. The microcapsules can also
include a combination of drugs tailored to a specific patient, and they
can be engineered for time release, providing longer-lasting therapeutic
effects within the patient's cancerous tissues.
"Overall, this
amounts to a combination of unique things that individually work, but
put together work much better," said Morrison. "Microcapsules are a
device that can be used together with ultrasound needles to mark the
biopsy site for diagnosis. They can also mark the perimeter and margin
of the tumor. When properly implemented, ultrasound can monitor the
progress of any tumor therapy with the new MEPS marker imaging
microcapsules being positioned within the tumor tissues, even if the
therapeutic delivered was not through the use of the MEPS
microencapsulation process."
In laboratory testing, MEPS-II
microcapsules containing anticancer drugs were injected directly into a
human prostate and lung tumors in animal models. These models were then,
in follow on tests, also injected following the delivery of specific
cryo-surgical effects, similar to a freeze and thaw effect on the
tumorous tissues. Injecting the microcapsules directly into the tumor
demonstrated improved site-specific therapeutic results and the
inhibition of tumor growth. Following cryo-surgery, the microcapsules
demonstrated improved destruction of the tumor better than freezing or
local chemotherapy alone.
Though Morrison's previous laboratory
studies of microcapsules were primarily focused on prostate and lung
cancer, his studies now target breast cancer for the FDA approval
process. Though it will take a few years to get approval to use the
microcapsules as a treatment option filled with anti-tumor drug
therapies, several devices that will aid in drug delivery are planned
for pre-clinical study as early as next year. NuVue's
ultrasound-enhanced needles and the imaging marker microcapsules, which
do not contain drugs, can be combined for use within the cancer patient.
After
achieving full FDA approval, planned clinical trials will involve
injecting the microcapsules with the anti-tumor drugs directly into
tumor sites in humans at both MD Anderson Cancer Center in Houston and
the Mayo Cancer Center in Scottsdale, Ariz. Given the success in animal
models in laboratory studies with human prostate and lung tumor
treatment, Morrison has high hopes in the near future, of being able to
begin use of the microcapsule treatment in breast cancer.
As
stipulated by Morrison and the NuVue research team, "these technologies
were only able to come to fruition because of the availability of the
microgravity environment aboard the space station. Without it, this
innovative breakthrough involving the microencapsulation technology
process would have never been created."
Just as microgravity can
aid in the discovery of new technologies for cancer treatment, these
microcapsules may one day aid in the recovery of breast and other
specific deep tissue cancers.
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