In April, interventional radiologist Ricardo Bracer, MD was the first in Alabama to perform an innovative cancer treatment. In fact, only 200 such procedures have been performed thus far across the nation. The chemotherapy embolization used a new type of microsphere that carries the chemo to the tumor site and releases it without dissolving the sphere. “It’s like practicing the medicine of the future today,” Bracer said. “It’s the first step of what will become the delivering of gene therapy and other agents.” The particles, called QuadraSpheres™ Expanding Microspheres, are tiny beads made of a material similar to soft contact lenses that can absorb certain types of medications. “The spheres are left in a solution of the chemotherapy,” Bracer said. “By negative charge, they absorb the agent, and once in the body, they lose that charge, and the chemo diffuses out of the sphere.” The sphere itself remains intact and continues to serve as an arterial blockage to the tumor, like other microspheres. Performing the treatment at Baptist Princeton, Bracer delivered the QuadraSpheres to the patient’s liver cancer through a small opening in the femoral artery in the inner thigh using micro-catheters to direct the spheres into the tumor. The patient was under conscious sedation during the procedure. Previously for this type of cancer, chemotherapy was injected into the blood vessels of the tumor. Then the vessels were plugged with microspheres. The new microspheres, however, form the blockage first before slowly releasing the chemotherapy they carry. “Therefore you have less systemic flow of the chemotherapy to the rest of the body, resulting in fewer side effects,” Bracer said. Combining chemotherapy drugs with the QuadraSpheres particles is considered an off-label use. The particles are FDA-approved for use in embolizing hypervascularized tumors and arteriovenous malformations. “We’re only using it to treat tumors in the liver right now, whether primary or metastatic,” Bracer said. “That’s because of the dual blood supply of the liver. It’s one of the organs that allows us to take out the arteries, but still receive blood supply to the normal tissue.” It’s not just the embolic aspect of the procedure that inhibits the microspheres’ usage, but also the spheres’ ability right now to absorb only certain medications. “QuadraSpheres are the first batch in which we can put doxyrubicin. It lends itself perfectly to this kind of sphere,” said Bracer, who foresees other agents being delivered soon in the spheres. Currently, the only curative option for liver cancer is a transplant and many patients are not candidates for transplant surgery. Bracer explained that his patient had no options left. One month after the initial procedure, an image comparison to the baseline taken after the first procedure showed tumor growth had been halted. In May, Bracer completed a second procedure on the same patient to block more vessels and deliver additional chemo. The tumor was being supplied by innumerable blood vessels, including some that didn’t come directly to the liver. “We found out last week that he actually had a lot of blood supplies that you couldn’t see the first time, because the others were in the way,” Bracer said. “This isn’t a magic bullet. We’re not curing tumors entirely. We’re preventing them from progressing. If we’re able to do that, then we’ve added time for him and hopefully quality of life.” Bracer said the microspheres offer physicians an extra tool to fight cancer, like external radiation and surgery. “Particularly with oncology patients where there’s no option, the spheres offer a little glint of hope where sometimes there’s none,” he said. “What’s exciting about the spheres is that it’s like the first aspirin before all the other medicines came out,” Bracer said, adding that research is now being conducted to adjust the permeability of the spheres to allow for the absorption of other agents. He thinks these could be seen on the market in the next six to twelve months. Beyond cancer, Bracer sees the potential for spheres to treat a myriad of conditions. BioSphere Medical, the makers of the QuadraSpheres, states that their patented platform technology has potential in tissue building, tissue repair and drug delivery. “Gene therapy is a good example,” Bracer said. “How can you create a sphere in which you can put different genes and then path that out?” Current research is exploring the delivery of agents to stimulate or stunt the growth of arteries. “That’s another thing that may be in the future where tumors are concerned,” Bracer said. “Tumors produce angiogenesis factors, and if we’re able to inject an agent that prevents that, then we’re preventing the tumor from creating roots, and it dies.” June 2008