Reports From the Field

Drug pump improves treatment response

The Food and Drug Administration recently approved two new uses for an implantable drug pump manufactured by Minneapolis-based Medtronic. The IsoMed Constant-Flow Infusion System received regulatory approval for use in a promising colorectal liver cancer treatment that delivers cancer-fighting medication directly to the liver, the most common place for colon cancer to spread, and for use in delivering morphine sulfate directly into the spinal fluid as a treatment for chronic pain.

"There are two reasons why patients respond better to treatment with the pump than to traditional treatment," says Elin Sigurdson, MD, director of surgical research at Fox Chase Cancer Center in Philadelphia.

"First, the pump delivers the drug directly into the liver. It’s not diluted in the blood. The second reason is that we can actually give much larger doses of the same type of drug than we can give systemically because the drug is cleared by the liver. As a result, response rates tend to be much higher," Sigurdson says.

Medicine flows constantly

For patients with colorectal cancer that has spread to the liver, the IsoMed Constant Flow Infusion System accurately delivers high concentrations of floxuridine on a continuous basis directly to the liver through the hepatic artery. The pump is surgically placed under the skin of the abdomen and filled with the appropriate medication. A catheter that runs from the pump to the hepatic artery delivers medication at a constant rate from the pump into the liver.

The IsoMed system also was approved for delivering morphine directly into the spinal fluid as a treatment for chronic pain in patients who have not found relief or who suffer intolerable side effects from oral or intravenous medications.

The implantable pump delivers small doses of analgesics directly into the fluid surround-ing the spinal cord, which contains the receptors that transmit pain signals to the brain. Compared with oral or intravenous administration, direct infusion often provides effective pain relief in small doses with fewer side effects.

Information on the implantable pump’s use for treatment of colorectal cancer is available on-line at Information on the pump’s use for treatment of chronic pain is available at