Cancer: A new 'drug sponge' may reduce chemo's toxic effects

The aim of the absorber is to minimize the toxic side effects of chemotherapy drugs.

(Online) - Researchers have developed an innovative, personalized absorber that can "catch" toxic chemotherapy drugs when they "leak out" of a treated organ. This could help reduce the adverse side effects of these cancer treatments. A team of researchers from institutions across the United States — including the University of California (UC), Berkeley, and the University of California, San Francisco (UCSF) — has recently developed a tiny device akin to a sponge, which is set to absorb chemotherapy agents after they have reached their target.

The aim of the absorber is to minimize the toxic side effects of chemotherapy drugs, which, although they have a potent effect against cancer tumors, also attack healthy organs and tissue and can impair their function.

The device is 3-D printed, so it can perfectly fit the vein of any individual receiving a chemotherapy treatment. Its absorbent polymer coating is able to "soak up" the toxic agents after they have passed through the organ that the treatment is targeting.

So far, the researchers have tested this new device as an aid to chemotherapy for liver cancer, as the therapeutic drugs travel to the liver in the bloodstream, which can increase the risk of toxic side effects.

The researchers have reported their experiments and findings in a study paper that has appeared today in the journal ACS Central Science.

To insert the innovative absorber, "Surgeons snake a wire into the bloodstream and place the sponge like a stent, and just leave it in for the amount of time you give chemotherapy, perhaps a few hours," explains Prof. Nitash Balsara, from the UC Berkeley.

The researchers tested the absorber in a pig model. They injected a chemotherapy drug for the treatment of liver cancer and found that, on average, the device was able to intercept 64 percent of the drug.

"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 chemotherapy," explains study co-author Prof. Steven Hetts.

However, he adds that "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."

In the future, the researchers aim to use this technique in the treatment of cancerous kidney tumors and brain tumors.

At the UCSF Mission Bay Hospitals, Prof. Hetts already uses a safer way of delivering chemotherapy drugs. Rather than simply injecting the drugs into the bloodstream, he inserts catheters into the veins to deliver them straight to the tumor site.

This approach already helps lower the risk of these potent drugs infiltrating and affecting healthy tissue. However, Prof. Hetts explains that more than half of the injected drug dose still tends to "leak out" of the targeted organ and reach other parts of the body.

The innovative absorber, which includes an ionic polymer that can effectively intercept the chemotherapy agent doxorubicin, would get rid of this problem. The concept for this device, the research team explains, actually comes from industrial refining processes.

"An absorber is a standard chemical engineering concept," says Prof. Balsara. "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," he notes.

Although the personalized absorber has so far performed well in the healthy pig model, the researchers stress that it is extremely important to validate it in clinical trials with human participants who are actually dealing with cancer.

"This is a first level in vivo validation that yes, this device will bind up drug in the bloodstream. But extensive animal testing is not the next path; the next path is getting conditional approval from [the US Food and Drug Administration (FDA)] to do first-in-human studies, because it is much more realistic to test these in people who have cancer as opposed to continuing to test in young pigs who have otherwise healthy livers," Prof. Hetts emphasizes.

Nevertheless, the researchers are confident that their innovative absorber is promising. They believe that it will not only be less invasive than other chemotherapy-filtering methods already under trial but is likely to perform better than them.

"There is a lot of opportunity to develop less-invasive devices that will bind up the drug in a gentler manner. We think this is a generally applicable concept," says Prof. Hetts.

"Because it is a temporary device, there is a lower bar in terms of approval by the FDA. I think this type of chemofilter is one of the shortest pathways to patients."