Two-Phase Therapy for Brain Tumors

Cancer researchers have developed a two-phase therapeutic method, immunotherapy followed by chemotherapy, which significantly reduces the ability of some brain tumors to develop drug resistance.

Investigators at Cedars-Sinai Medical Center (Los Angeles, CA, USA) studying a highly aggressive type of brain tumor called glioblastoma multiforme (GBM ) focused their efforts on tyrosinase-related Protein (TRP)-2. Tumor cells that express TRP-2 rapidly develop resistance to chemotherapeutic drugs. However, TRP-2 is a potent antigen, and the immune response to its presence launches cytotoxic T lymphocytes that diminish or deplete the number of TRP-2-containing tumor cells. Tumor cells that survive the immune attack are usually quite sensitive to anti-cancer drugs.

In the current study, the investigators removed immune dendritic cells and tumor cells from a group of patients. The cells were grown together in tissue culture, and the dendritic cells were then injected back into the patient. Patients were then given chemotherapy.
Results published in the May 16, 2005, online edition of Oncogene revealed that the two therapies together were able to accomplish results that neither could achieve by itself. The average length of patient survival was extended to about 26 months, compared to 18 months for those receiving dendritic cell vaccine alone and 16 months for those undergoing chemotherapy alone.
Senior author Dr. John S. Yu, co-director of the comprehensive brain tumor program at Cedars-Sinai Medical Center, said, "It is important to note also that four patients in our study that demonstrated a response to TRP-2, after tumor recurrence, responded to chemotherapy with what oncologists call complete responses, which means the tumors were no longer visible on MRI.”




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