Chemical ‘Sponges’ Soak up Toxic Chemotherapy Drugs

A new device soaks up chemotherapy drugs before they can circulate widely throughout the body, enabling higher doses and limiting off-target effects in other organs.

The ChemoFilter system, developed by researchers at the Lawrence Berkeley National Laboratory (LBL, Berkeley, CA, USA) and the University of California (UC, Berkeley, USA), is comprised of a nickel-titanium metal frame (in a collapsible flower-petal array), attached to a thin polymer membrane that can be expanded out into a blood vessel from within a catheter. The polymer membrane contains polyethylene for strength and flexibility, as well as sulfonic acid, which has a negative electric charge that attracts and binds drug molecules.

Certain types of chemotherapy drugs, such as doxorubicin, which is used to treat liver cancer, have a positive charge, so the polymer membrane material can bind the drugs via their electric charge, while allowing other types of molecules to flow through. In a preclinical study, a ChemoFilter device was inserted into a pig and was found to reduce the peak concentration of the doxorubicin by about 85%. According to the researchers, the drug-capture system could also potentially be applied to antibiotic treatments.

“Doxorubicin has been around for decades. It is very well understood, and it is also very toxic. If you get exposed to too much, when it goes through the heart you can go into heart failure,” said interventional neuroradiologist Steven Hetts, MD, of the University of California, San Francisco (UCSF; USA), inventor of the ChemoFilter, who specializes in treating eye tumors. “You can get very high concentrations of that chemotherapy in the eye and relatively low concentrations in the rest of the body, but some will wash through the eye and into the veins in the head, so you can have side effects from that.”

“We used to use this material for transporting protons in a fuel cell. I was really excited when I found out this could be used for chemotherapy - this was branching out in a totally different direction,” said lead researcher X. Chelsea Chen, PhD, a postdoctoral researcher at LBL. “We are actively searching for new materials and mechanisms for the polymer membranes. Researchers are exploring the use of 3D-printed materials, for example, that can be coated with charged particles to attract and bind drug molecules.”

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University of California, San Francisco