Pancreatic cancer is the third leading cause of cancer deaths in the U.S., in part because it is very difficult for chemotherapy drugs to reach the pancreas, located deep within the abdomen.

Now, researchers from MIT and Massachusetts General Hospital may have scaled that hurdle. The team has developed a small, implantable device that delivers chemotherapy drugs directly to pancreatic tumors. In a study of mice, they 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.

This thin, flexible film could also be adapted to treat other hard-to-reach tumors, according to the researchers, who described the device in the journal Biomaterials.

The MIT and MGH team launched this project a little more than three years ago with a focus on pancreatic cancer, which has a five-year overall survival rate of less than 6 percent. Injections of chemotherapy drugs often fail not only because the pancreas is so deep within the body, but also because pancreatic tumors have few blood vessels, making it harder for drugs to get in. Also, pancreatic tumors are often surrounded by a thick, fibrous coating that keeps drugs out.

In hopes that getting drugs directly to the tumor 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 tumor.

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 tumor, minimizing side effects on nearby organs.

The researchers compared two groups of mice carrying transplanted human pancreatic tumors. 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, tumor growth slowed, and in some cases tumors shrank. The localized 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 tumors of mice with the implanted device was five times greater than in mice that received injections. Also, because there are so few blood vessels in pancreatic tumors, the drug tended to remain there and not spread to nearby organs, preventing toxic effects in healthy tissues.

The researchers are now preparing to design a clinical trial for human patients. While they began this project with a focus on pancreatic cancer, they expect that this approach could also be useful in treating other tumors that are difficult to reach, such as tumors of the gastrointestinal tract.

The film could also be used as a coating for a stent. Pancreatic cancer patients often suffer from blockage of the bile duct, which interferes with digestion and is very painful. The duct can be reopened with a stent but usually gets blocked again eventually, requiring the patient to have the old stent removed and a new one inserted.

Coating stents with a drug-releasing film could help prevent the cancer cells from spreading into the duct and blocking it again. “We can extend the lifespan of these devices,” says Laura Indolfi, a postdoc in MIT’s Institute for Medical Engineering and Science and the MGH Cancer Center, who is one of the study’s lead authors. “Rather than being replaced every month they could be replaced every six months, or once a year.”