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The strategy: occlude vessels
feeding prostate cancer cells
By DON LONG
Medical Device Daily National Editor
James Bond lies tied down, legs spread, a laser pointed
at his nether regions (remember that scene from
“Goldfinger”).
That disturbing image just might pop into the mind of
a prostate cancer patient, when told of the therapy being
developed by Steba Biotech (New York), a company using
laser technology for activation of a material for killing
prostate cancer cells.
Not to worry, assures CEO Douglas Altschuler, the laser
energy Steba uses is extremely low-level, more like “activated
light,” and delivered much like standard brachytherapy
treatment of the prostate – thus a life-saver rather than
an instrument of torture.
Key to the strategy is the use of a photosensitizer
which, when activated by light, occludes the blood vessels
that feed a tumor. Close down these vessels and you kill the
tumor, is Steba’s theory, and an alternative to directly
attacking the tumor itself with surgery, chemotherapy or
the use of radiation.
While the company’s strategy is a standard phototherapeutic
method, the key is the use of a non-standard material
– rather than activation of a prodrug – to provide the vessel-killing
effect.
Steba is using a material called WST11, which it describes
as a photosensitizer. WST11 is a derivative of natural bacteriochlorophy,
developed in a collaborative effort between
Steba, Negma Lerads (Paris), and the Weizmann Institute of
Science (Rehovot, Israel). The material is licensed by Steba
from Weizmann.
Steba notes that the vascular-occluding effects of photodynamic
therapy have been known for some time, and
with the potential for treating tumors. But it says that the
previous attempts to destroy tumors via vascular destruction
had been less than optimal because various photosensitizers
remained in the cells of normal tissue, causing prolonged
toxicity.
By contrast, WST11 clears from the body entirely in just
30 minutes, Altschuler told MDD.
The material, he said, is derived from “a chlorophyll that
is generated by bacteria which grows in the dark . . . it does
not need sun. We take it to our facility in Israel, modify it
and stabilize it.” He said this material is “neutral, non-toxic,”
and termed the overall approach “green biology.”
After injection into the tumor cite, the material is activated
by laser light. Developed in collaboration with Israeli
laser firm Egen (Tel Aviv), the laser is extremely low-powered,
Altschuler noted, and “is as much of a computer as a
laser. It measures the light power within the tumor, and
uses a feedback loop and shuts off, and reports all the
information about the procedure.”
MEDICAL DEVICE INNOVATION 2010
The activating light is delivered by fibers inserted near the
prostate, in much the same way as the delivery of brachytherapy,
then removed. And the company will market the technology
only to those already providing brachytherapy, Altschuler
said, so that the required training will be minimal.
When activated by the laser light, the material serves to
occlude the blood vessels, turns them “necrotic,’ and
leaves, under MR imaging, only “a black hole,” he said.
Importantly, the technique exploits the difference
between blood vessels within a cancerous tumor, and
blood vessels within normal tissue, he noted.
The company currently is conducting a multi-center,
dose-ranging trial at five sites, one in Canada and four in
Europe and the UK, with enrollment of 40 patients. It is developing
additional sites throughout Europe for this trial and
will follow up with a smaller dose-ranging trial in Europe.
The next step is pursuit of a Phase II trial in the U.S.
Altschuler said the company soon will be talking to the
FDA to develop the protocols for this trial, and he acknowledged
that a key challenge will be to get the agency “to
understand what kind of trial we need to do – nothing like
this has ever been done before.” But he said that the company
hopes these protocols can be worked out so that the
U.S. trial can be launched this summer.
To date, Steba reports procedures performed on somewhat
more than a dozen men and said it is “quite pleased
with the early signals of efficacy.” It also reported being in
the “early stages” of preparation to report its data.
Altschuler said that the company is “completely, privately
self-funded,” and able to draw on €130 million to pursue
the development of the application for prostate cancer.
He spoke yesterday to MDD on his way to the airport to
talk to investors in Los Angeles, but said any potential
funds developed from here on out are intended to be used
for the company’s development of its next-generation
application, the treatment of macular degeneration.
He noted that a good bit of photodynamic therapy had
been used for treatment of macular degeneration but that
this approach was quickly swamped by new drug treatments,
particular the use of Lucentis, now standard therapy.
But he said that Lucentis treatments are too frequent
and eventually fail.
Steba plans to use its photodynamic therapy strategy
in combination with drug treatment to provide equal or
better outcomes and with fewer treatments.
Atlschuler acknowledged he can’t predict a timeline for
commercialization of the prostate therapy application, but
said that the company clearly prefers a “two-to-three-year
window,” rather than one of five to six years.
With an already established career in device development
and photodynamic therapies, Altschuler understated
by saying he sees Steba’s technology as a potential winner
– adding: “I have a nose for these things.”
(This story originally appeared in the Feb. 11, 2009, edition
of Medical Device Daily)
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