Boston researchers are bringing new cancer drug delivery technologies to the clinic.

Mason Inman

Cancer treatments are notorious for being blunt instruments; chemotherapy and radiation kill healthy cells along with cancerous ones, causing major side effects.

Now, researchers are using new tools in nanotechnology to create more-targeted treatments. Boston-area researchers— engineers and materials scientists working alongside biologists and drug developers—are leaders in coming up with new ways of delivering drugs and other therapies that promise greater precision and reduce the likelihood of side effects. Some researchers are beginning to take that technology to the clinic.

Much of this Boston-area work is coming out of the MIT-Harvard Center of Cancer Nanotechnology, which opened in 2006. It is one of seven nanomedicine centers across the United States funded by multimillion-dollar grants from the National Cancer Institute (NCI).

“This isn’t about getting papers published,” says Omid Farokhzad, who is a member of the MIT-Harvard center and a physician at Brigham and Women’s Hospital. “The goal [set out by the NCI] is clinical translation of this nanotechnology work and doing that fast.”

Polymer balls

Farokhzad and chemical engineer Robert Langer of MIT are co-leaders of a project at the MIT-Harvard center that’s developing nanoparticles to carry cancer drugs.

The core of the tiny particle is made of two biodegradable polymers called PLGA and PEG, which can bind to a wide range of drugs and are already used in some medical devices and drug formulations. Special coatings on the outer surface of the nanoparticles enable them to home in on specific diseased cells. For example, cancer cells often have protein receptors on their surface that normal cells don’t have, so molecules on the surface of the particles are designed to bind to only those receptors and trigger the cells to engulf the particles. Once inside the cells, the particles slowly degrade, releasing their drug payload.

Langer and Farokhzad recently founded a Cambridge-based company, BIND Biosciences, to further develop the technology for a variety of diseases. By 2009, they plan to start clinical trials of these nanoparticles to treat prostate cancer.

RNA packages

Nanotechnology is also the basis for new ways of ferrying short interfering RNAs (siRNAs), which hold promise for treating cancer and other diseases. Once inside cells, these snippets of RNA can silence specific genes through the mechanism called RNA interference.

But developers of siRNA drugs face a major hurdle—it’s difficult to get these fragile molecules past the body’s defenses and into specific cells. Researchers are working on different methods of delivering siRNAs. The most advanced is the use of liposomes, nano-sized bubbles of fat molecules that contain drugs such as small RNA molecules, says Dan Anderson, a researcher in Langer’s lab and also a member of the MIT-Harvard center.

In unpublished studies, these tiny carriers appear to be effective in delivering siRNAs in several animal species, Anderson says.

The technology is already moving into clinical trials. Cambridge-based biotech company Alnylam Pharmaceuticals, one of two leading companies in the United States working on siRNA treatments, is packaging an siRNA for liver cancer in these liposomes and plans to begin testing them in humans next year. It will be one of the first clinical trials to test anti-cancer siRNAs.

Hurdles remain. For one, the liposomes are made of fat molecules that don’t occur naturally. “I’m not sure how the [U.S. Food and Drug Administration] is going to look at them,” Anderson says. “They’re brand-new materials that have never been made before.”