New implantable device may help shrink pancreatic tumours

Washington: MIT researchers have developed a small, implantable device that delivers chemotherapy drugs directly to pancreatic tumours, and can potentially help shrink the tumours to a size where a surgeon can remove them.

In a study of mice, researchers found that this approach was up to 12 times more effective than giving chemotherapy drugs by intravenous injection, which is how most pancreatic cancer patients are treated. "It is clear there is huge potential for a device that can localise treatment at the disease site," said Laura Indolfi, from Massachusetts Institute of Technology (MIT)'s Institute for Medical Engineering and Science (IMES).

"You can implant our device to achieve a localised drug release to control tumour progression and potentially shrink (the tumour) to a size where a surgeon can remove it," said Indolfi. This thin, flexible film could also be adapted to treat
other hard-to-reach tumours, researchers said.

Injections of chemotherapy drugs often fail not only because the pancreas is so deep within the body, but also because pancreatic tumours have few blood vessels, making it harder for drugs to get in. Also, pancreatic tumours are often surrounded by a thick, fibrous coating that keeps drugs out.

In hopes that getting drugs directly to the tumour site would improve treatment, the researchers engineered a flexible polymer film that is made from a polymer called PLGA, which is widely used for drug delivery and other medical applications. The film can be rolled into a narrow tube and inserted through a catheter, so surgically implanting it is relatively simple.

Once the film reaches the pancreas, it unfolds and conforms to the shape of the tumour. "Because it is very flexible it can adapt to whatever size and shape the tumour will have," Indolfi said. Drugs are embedded into the film and then released over a preprogrammed period of time.

The film is designed so that the drug is only secreted from the side in contact with the tumour, minimising side effects on nearby organs. Researchers, including those from Massachusetts General Hospital, compared two groups of mice carrying transplanted human pancreatic tumours.

One group received the drug-delivery implant loaded with the chemotherapy drug paclitaxel, and the other received systemic injections of the same drug for four weeks, which mimics the treatment human patients usually receive. In mice with the drug-delivery implant, tumour growth slowed, and in some cases tumours shrank.

The localised treatment also increased the amount of necrotic tissue (dead
cancer cells that are easier to remove surgically). Additionally, by acting as a physical barrier, the film was able to reduce metastasis to nearby organs.

The researchers also found that after four weeks, the concentration of paclitaxel in the tumours of mice with the implanted device was five times greater than in mice that received injections. The research was published in the journal Biomaterials.