CHAPEL HILL, NC -- A drug-impregnated wafer that releases chemotherapy directly to tumors that have spread to the brain from other cancers is now undergoing safety tests in patients.
Results of this multi-center phase-I clinical trial may have implications for treatment aimed at prolonging the survival of an estimated 50,000 patients in the U.S. with brain cancer metastases, according to principal investigator Dr. Matthew Ewend, assistant professor of neurosurgery at the University of North Carolina at Chapel Hill School of Medicine.
The Food and Drug Administration has already approved the biodegradable polymer wafer for treatment of recurrent malignant primary brain tumors, those originating within the brain itself. Surgically placed into the brain alongside the malignancy, the dime-sized wafers have been shown to improve survival at six months by more than 50 percent. "Average survival with these brain tumors is less than one year. This treatment helps prolong that," the UNC-CH neurosurgeon says.
Ewend likens the wafer to a bar of soap slowly eroding in the shower. "The drug within the wafer reaches the surface and is released into the brain. But the drug that's inside the 'bar of soap' is protected; the water can't get in and deactivate it."
The polymer package for the chemotherapy wafer was initially developed in the 1980s at M.I.T. by Dr. Robert Longer. Animal and human studies led by Johns Hopkins University neurosurgeon Dr. Henry Brem pioneered the wafer's development and led to its approval by the FDA. The wafer contains the drug 1,3,bis(2-chlorethyl)-1-nitrosourea, or BCNU, the only FDA-approved drug for the treatment of primary brain tumors.
According to Ewend, about 20,000 cases of primary brain tumor occur each year in the U.S. compared to about 50,000 metastatic brain malignancies, of which 90 percent arise from lung, breast, and melanoma skin cancers.