New Agent in Radiation Oncology to Treat Solid Tumors

The antibody trastuzumab (Herceptin) has provided a significant benefit to patients undergoing treatment for breast cancer. This therapy has been successful in patients with a high number of HER-2 receptors on tumor cells. HER-2 receptors can also be found on many other solid tumors; however, HER-2 expression is only high enough in about 20% of cases for Herceptin alone to be effective. Conjugating the antibody to a powerful radioisotope allows for the targeting and destruction of cancer cells with lower HER-2 expression such as colon, ovarian, pancreatic, and gastric cancers. AREVA Med is sponsoring a trial using Herceptin to carry an alpha-emitting radioisotope, 212Pb. In preclinical studies, this form of radiation has been shown to be very cytotoxic to targeted cells while sparing normal surrounding cells, due to the short path length of the alpha particle. Prior UAB ovarian cancer clinical trials, using radiolabeled antibodies injected into the abdomen, resulted in enhanced survival without evidence of disease in a portion of patients. The new agent, 212Pb-TCMC-Trastuzumab, has been authorized by the FDA to be administered to patients who have failed standard therapy and have HER-2 expressing tumors mainly in the abdomen. More details about this study, Phase I Trial of Intraperitoneal 212Pb-TCMC-Trastuzumab for HER-2 Expressing Malignancy, can be found at clinicaltrials.gov and the UAB Comprehensive Cancer Center website.