MEDICAL DEVICE INNOVATION - Medical Device Daily

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Sponge-like polymeric discs
offer new cancer strategy
By DON LONG
Medical Device Daily National Editor
What’s better — to invent or to innovate
Invention, of course, can get you into the history books,
though inventors often miss out on the value of the resultant
products.
Innovation, by contrast, is considerably easier because
you can use available technologies – and get more quickly
to market – and to the clinic, importantly, in the case of
medicine.
Taking available technologies and putting them
together in a sophisticated new way is the strategy being
employed by David Mooney, PhD, and a group of bioengineers
and medical collaborators at Harvard University
(Cambridge, Massachusetts).
They are using polymers commonly employed in
device technology, combining these with standard
approved drugs, to develop a new pathway for the delivery
of vaccines and, they hope, further out, for reengineering
the human immune system against diseases.
In his lab, Mooney and his team used biodegradable
polymers similar to those used in sutures and other materials
to create small discs (about 8.5 mm across) that are
implanted beneath the skin – similar to contraceptives that
are implanted in a woman’s arm.
The implants are about 90% air and somewhat comparable
to a sponge, he told Medical Device Daily. The discs
incorporate drugs and antigens which interact with the cellular
physiology of the body to attack cells that may develop
into tumors.
Implanted in rats for this study, the strategy destroyed
an aggressive form of melanoma – a form that would kill
the rodents in 25 days, the researchers said – in 90% of the
rats. And they said this approach could turn out to offer the
most effective strategy for delivering a cancer vaccines.
“We purposely took things [for the study] that all had an
established safety record in humans,” Mooney told MDD,
rather than inventing. “We took some standard pieces and
put them together.”
He said also that the system can be used with drugs
already in general use and that the primary challenge in the
method is “to get the drug to recognize the type of cancer.”
The approach of this research is to manipulate the cells
already in the body as opposed to a method that Mooney
said has been attempted without great success.
Previous work on cancer vaccines, he said, has focused
on removing immune cells from the body and reprogramming
them to attack malignant tissues. The altered cells are
then re-injected into the body.
Theoretically and according to the evidence supporting
this approach, he said, this should work. But he noted
MEDICAL DEVICE INNOVATION 2010
that the work utilizing this technique has shown that more
than 90% of the re-injected cells die before having any
effect.
By manipulating the cells already within the body, as in
this study, the strategy also may be usable for boosting the
body’s immune system to fight off other diseases, Mooney
said. And the focus of the team’s research is more on a preventive
approach rather than on exploring the therapeutic
pathway versus diseases already attacking the body.
“We’ve been very interested for a number of years in
cell therapies in the context of regeneration,” he said. “But
we began to think, a couple of years ago, that it would be
greatly preferable if we could control cells that already
existed within the bodies instead of transplanting cells.”
The transplantation process, he called “awkward and
expensive,” and that it is “much nicer do all the manipulation
in the body.”
Further explaining the approach, Mooney said that the
drugs and cytokines bioengineered into the discs act to
attract “immune-system messengers” called dendritic cells.
The dendritic cells then report to nearby lymph nodes,
“where they activate the immune system’s T cells to hunt
down and kill tumor cells throughout the body.”
In essence, he said that the discs are used to “mimic the
danger . . . that activate these cells. They know they’ve seen
something foreign so that travel to the lymph nodes . . . and
go find the tumor” and destroy it.
While Mooney’s group focuses on creating the discs, he
emphasized the important collaboration with medical school
researchers at Harvard, citing especially the work of Glenn
Dranoff MD, of the Dana-Farber Cancer Institute (Boston).
Researchers there, he said, developed some of the cancer
vaccines in clinical trials . . . and provided a tremendous
amount of assistance in term of the immunological aspect.”
The next steps for this research
The collaborators will continue to study this approach,
Mooney said, and, in the meantime, a parent is being
sought and the method has been licensed to InCytu
(Lincoln, Rhode Island), which he described as “a small startup
company.”
As with all of the basic research approach, Mooney told
MDD it is “very hard to predict” when the method will reach
general use for patients.
But he said that the attempt was to ‘take an approach
where that, hopefully, would not be too long. All the components
of this system are routinely used in patients today,
and all the components have safety profiles that are very
good.”
Based on “the way we combine things,” Mooney said,
the hope is to move the method “quickly to the clinic.”
Mooney and his Harvard colleagues describe the
research in the current issue of the journal Nature
Materials.
(This story originally appeared in the Feb. 2, 2009, edition
of Medical Device Daily)
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