In contrast, when the drug is injected into the tumor without being encapsulated inside particles, it has little effect, and the tumor continues growing. Apparently, the drug diffuses out of the tumor area before it can kill off all the cancer cells.
Early toxicity trials of the nanoparticles could begin in two years, if further animal studies go well, says Farokhzad.
The drug-delivery technology is part of a larger effort by researchers to use nanotechnology to revolutionize cancer treatment. Joseph DeSimone, chemistry and chemical engineering professor at the University of North Carolina at Chapel Hill and North Carolina State University, for example, has recently started mouse trials using his own polymer-based nanoparticles for drug deliver. University of Michigan physician James Baker’s nanoparticles based on highly branched structures called dendrimers have also shown success against cancer in rodents.
The MIT-Harvard researchers are also working on targeting pancreatic cancer and eventually breast cancer and cardiovascular disease. Henry Brem, neurosurgeon and director of the department of neurosurgery at Johns Hopkins University School of Medicine, would like to adapt the nanoparticles for brain cancer, especially for treating tumors difficult to reach with surgery. “It’s not going to affect the brain, it will only affect the tumor cells. To just inject it into the tumors and eradicate them, that would be a huge step forward for neural oncology. If we could get a hold of it, we would do it tomorrow, in the laboratory,” he says.
Eventually, the MIT-Harvard researchers hope to design nanoparticles that can be injected into the bloodstream, from which they could seek out cancer cells anywhere in the body, making it possible to treat late-stage metastasized cancer. “Even though this represents a small percentage of patients that actually have the disease, these are the ones that have no therapeutic option available to them,” Farokhzad says. “So the idea of having nanoparticles that can circulate through the body, find cancer cells, and kill them, is very, very attractive.”
To this end, they are generating “libraries” of nanoparticles of various sizes with different chemical properties and molecular attachments, which they will test in vitro and in vivo to identify those that are most effective at finding and destroying cancer cells without becoming lodged in healthy organs.