UCLA'sJonsson Cancer Center is testing an experimental immune system-boostingantibody that could one day help women who have not responded to conventionalchemotherapy treatments for metastatic breast cancer.
The Phase I study uses an antibody directed atthe MUC1 protein, which is exposed on the surface of cancer cells in more than90 percent of women who have breast cancer. In normal tissues, MUC1 is aprotein that is literally sugar-coated, being completely surrounded bycarbohydrate molecules. In rapidly growing cancer cells, the sugar structuresdo not form correctly and the protein core of MUC1 is exposed. Researchersbelieve this exposed protein core can become a new target that is vulnerable toattack by antibodies.
In laboratory studies, the antibody called R1550(formerly Therex) has been shown to bind tightly to MUC1 on cancer cells andthen activate immune system cells to kill the cancer. Using antibodies toencourage the body's own immune system to do its job is a different way offighting cancer. Other targeted therapies help cancer-killing drugs workbetter, but this study seeks to engage the natural immune system cells to dothe killing.
"Our study is a real test of an antibody as immunotherapyfor breast cancer. The way this antibody works seems to be dependent upon itsability to engage the immune system after it binds to MUC1 on the tumor cells,"said Dr. Mark Pegram, director of the Women's Cancer Program Area at UCLA'sJonsson Cancer Center and principal investigator for the study. "Sadly, womenwho have not responded to chemotherapy don't have too many other treatmentoptions. We believe this antibody has the potential to be a less toxicalternative to conventional chemotherapy treatment for women with recurrentbreast cancer."
Theresearch study is recruiting women volunteers who have already been treatedwith the chemotherapy drugs Taxol or Taxotere and an anthracycline drug such asAdriamycin, but who have relapsed despite prior treatment.
Anearlier study conducted in the United Kingdom showed the antibody waswell-tolerated in breast cancer patients.
UCLA'sJonsson Cancer Center is currently the only site in the world testing this newantibody, Pegram said.
Interested volunteers should call (888) 798-0719 to see ifthey qualify to participate in the study.
For more informationabout UCLA's Jonsson Cancer Center, visit our Web site at www.cancer.mednet.ucla.edu/.