- A device acting like a 'drug sponge'
has been developed that can soak-up toxic drugs in the bloodstream
- Excess chemotherapy drugs leaving a
cancerous organ can be soaked-up by the 'drug sponge' inserted in a vein
emerging from the target organ
- This can significantly minimize the
spread of toxicity to other parts of the body
A polymer-based 'drug sponge' can be used
to absorb excess drugs when inserted into the bloodstream. This sponge can
soak-up toxic chemotherapy drugs used for the treatment of liver cancer, which
only responds to aggressive therapies, using large doses of drugs like
The 'drug sponge'
is made of an
absorbent polymer that coats a 3D-printed cylindrical scaffold resembling a
shunt, which fits tightly into a vein leaving the target organ, so that the
surplus toxic drug is absorbed by the sponge. This prevents the drug from
causing toxicity to other organs of the body.
‘A ‘drug sponge’ has been developed that can absorb toxic drugs from the bloodstream. When chemotherapy drugs are delivered to a cancer site, the surplus drug leaving the organ can be soaked-up by the ‘drug sponge’, inserted in a vein exiting the target organ. This will minimize the toxicity to other parts of the body.’
The study was jointly led by Dr. Nitash Balsara, PhD and Dr.
Steven Hetts, MD. Dr. Balsara is a Professor of Chemical and Biomolecular
Engineering at the University of California, Berkeley (UCB) and a Faculty
Associate Scientist at the Lawrence Berkeley National Laboratory, Berkeley, California,
USA. Dr. Hetts is a Professor of Radiology at the University of California, San
Francisco (UCSF) and Chief of Interventional Neuroradiology at the UCSF Mission
Bay Hospitals, San Francisco, USA.
The study has been published in the journal ACS Central
, an open-access publication of the American Chemical Society.
How was the 'Drug Sponge' Conceptualized?
The 'drug sponge' was conceptualized by
Hetts, while treating cancer patients with chemotherapy drugs, which he
delivered with the help of a catheter so that the drug is released very close
to the target organ. This ensures that the tumor receives the maximal dose,
causing minimal toxicity to the rest of the body, thereby substantially
reducing side-effects. This is much better than the conventional approach,
where the chemotherapy drug is directly injected into the bloodstream, which
causes widespread toxicity throughout the body. Moreover, by this method, more
than 50 percent of the drug fails to reach the target organ. Hetts conceptualized
that if the excess chemo drug leaving the target organ could be filtered out,
much less drug would enter the circulation, thereby significantly reducing
toxicity to other organs.
How was the 'Drug Sponge' Developed?
The 'drug sponge' was developed by Balsara
and his team at his UCB laboratory. The sponge is based on ionic polymers that
are used in batteries and fuel cells. After screening various types of
polymers, a polymer was identified that was capable of absorbing
absorber is a standard chemical engineering concept,"
Balsara said. "Absorbers are used in petroleum refining to remove unwanted chemicals
such as sulfur. Literally, we've taken the concept out of petroleum refining
and applied it to chemotherapy."
The new absorbent polymer was
commercially produced in large quantities and the technology was tweaked so
that it could adhere to a 3D-printed cylinder. Crisscrossing struts were
incorporated on the surface of the cylinder, onto which the polymer was
attached, so that the whole device could be inserted into a patient's vein.
the cylinder in the vein is important; if the fit is poor, then the blood with
the dissolved drug will flow past the cylinder without interacting with the
The size and dimension of the 3D-printed
cylinder were customized
so that it could fit into the vein of each
patient, who may have different vein diameters. This was engineered by Carbon
Inc., a company specializing in 3D-printing, based in Redwood City, California,
After implanting the 3D-printed device
into the vein of a healthy pig, Hetts measured how much of doxorubicin
, injected upstream, was absorbed by
the 'drug sponge' device, placed downstream. He found that approximately 64
percent of the drug was absorbed.
How Can the 'Drug Sponge'
Since most anticancer drugs are highly
toxic, the doctors need to regulate the dose in such a way that it is high
enough to kill the cancer cells, but not high enough to cause toxicity to the
other organs of the body. In spite of this, chemo drugs cause many serious
side-effects, including nausea, vomiting, hair loss, diarrhea, ulcers
, as well
as immunosuppression, which suppresses the body's defense system, so that it
can't fight back.
The present study has evaluated the
efficacy of the 'drug sponge' in a liver
model using the chemo drug doxorubicin.
In this regard, Hetts said: "We are developing this around liver cancer
because it is a big public health threat - there are tens of thousands of new
cases every year - and we already treat liver cancer using intra-arterial
He added: "But if you think about it, you could use this sort of approach for any
tumor or any disease that is confined to an organ, and you want to absorb the
drug on the venous side before it can distribute and cause side-effects
elsewhere in the body. Ultimately, we would like to use this technology in
other organs to treat kidney tumors and brain tumors."
Now that the 'proof-of-principle' has
been established in pigs, the researchers want to take it to the next level
i.e. human testing. They are seeking approval from the US Food and Drug
Administration (USFDA) to directly proceed to "first-in-human" studies without
having to do further animal studies. They opine that this will be much more
realistic as liver cancer is primarily a problem in humans and not in pigs. The
research team is optimistic that since the device is for temporary use, the FDA
will likely set lower criteria for approving it for clinical testing.
study indicates that the 'drug sponge' device could also be applied for other
types of cancers, as well as other classes of chemo drugs. Moreover, the same
technology could be used for soaking-up other types of toxic drugs such as
antibiotics, which can potentially cause kidney damage.References :
- 3D Printed Absorber for Capturing Chemotherapy Drugs before They Spread through the Body - (https://pubs.acs.org/doi/10.1021/acscentsci.8b00700)