The first in a new generation of nanotechnology-based cancer treatments will likely begin clinical trials in 2007, and if the promise of animal trials carries through to human trials, these treatments will transform cancer therapy. One of these new approaches places gold-coated nanoparticles, called nanoshells, inside tumors and then heats them with infrared light until the cancer cells die. Because the nanoparticles also scatter light, they could be used to image tumors as well. The spheres are small enough (about 100 nanometers in diameter) to slip through gaps in blood vessels that feed tumors. So as they circulate in the bloodstream, they gradually accumulate at tumor sites.
“We shine light through the skin, and in just a few minutes, the tumor is heated up,” Halas says. “In the studies that were initially reported–and this has been repeated now more than 20 times in at least three different animal models–we have seen essentially 100 percent tumor remission.” The tests also suggest the nanoshells are nontoxic. Halas says they are eliminated from the body through the liver over several weeks. The technology was developed at Rice in collaboration with Jennifer West, a professor of bioengineering. It has been licensed by Nanospectra Biosciences, a startup based in Houston, TX, that is beginning the process of getting FDA approval for clinical trials for treating head and neck cancer. In the future, the technology could be used for a wide variety of cancers.
“There is a potential for this to bring a profound change in cancer treatment,” Halas says. “For the case of someone discovering a lump in their breast, this would mean that a very simple procedure could be performed that would induce remission.” She says that “for many, many cases of cancer, rather than the lengthy chemotherapy or radiation therapy,” an individual would have “one simple treatment and very little side effects.”
Halas anticipates that approval for the method will come quickly, in part because the nanotechnology is not a drug but a device, for which the approval process is simpler. Also, she expects it will perform the same in humans as in animal models, “because heat and light work in exactly the same way whether you’re in a pig, a dog, [or] a human being.”
Since their initial experiments, the researchers have been further developing the technology. They’ve demonstrated the ability to coat the nanoshells with antibodies that latch on to breast-cancer cells, further improving the selectivity of the treatment. They’ve also attached molecules that make the nanoshells into pH sensors that would be useful for both imaging tumors and as an “optical biopsy” for identifying cancers, Halas says.
The clinical trials this year will not take advantage of these advances. But eventually the antibody targeting could make preventative cancer treatments possible.
Beating cancer would of course be a huge deal. If we had a lock on fighting cancer we could also more aggessively try regenerative medicine that could regrow parts of the body but which might increase cancer risk. We could get the benefits without concern about the cancer if we could handle the cancer easily.