The Food and Drug Administration has approved the chemotherapy agent Temodar® (temozolomide) for the initial treatment of glioblastoma multiforme. The new approval indicates that Temodar® should be used during radiation therapy, as well as following radiation therapy in newly diagnosed patients.1 Temodar® was previously FDA-approved for the treatment of recurrent astrocytomas.
Approximately 20,000 people are diagnosed with primary brain cancer in the United States each year. Primary brain cancer is cancer that originates in the brain and has not spread from cancer already located elsewhere in the body. Glioblastoma is one of the most common, and aggressive, types of primary brain cancer. When glioblastoma is present, glial cells become malignant and grow out of control. Glial cells are the most abundant cells present in the nervous system, providing many supportive functions that facilitate the majority of processes conducted by neurons (cells that transmit impulses between the brain, spinal column and nerves). Standard treatment options for glioblastoma consist of surgical removal of the cancer if possible, radiation therapy and/or chemotherapy. However, even with the most aggressive treatment available, most patients will survive less than one year after diagnosis. Because of the poor prognosis for patients with this disease, researchers are attempting to develop more effective treatment strategies to improve survival and/or improve quality of life of glioblastoma patients.
One obstacle in the treatment of brain cancer is the inability of the majority of chemotherapy agents to penetrate the blood-brain barrier. The blood-brain barrier is a membrane that surrounds the brain and spinal cord and protects the brain and nervous system by allowing only very select molecules to pass through. Temodar® is a chemotherapy agent that has the ability to penetrate the blood-brain barrier and provide anti-cancer effects in the brain. Results from previous clinical studies have indicated that Temodar® in addition to radiation therapy as initial treatment may provide improved survival for patients with glioblastoma multiforme.
The trial that prompted FDA-approval for Temodar® was conducted by researchers affiliated with the European Organization for Research and Treatment of Cancer (EORTC) and the National Cancer Institute of Canada (NCIC). 2 The clinical trial directly compared the combination of Temodar® and radiation therapy to radiation therapy alone in patients with glioblastoma multiforme. This trial included 573 patients with newly diagnosed, stage IV glioblastoma multiforme. Patients were divided into two groups: one group was treated with radiation therapy only and one group was treated with the same radiation therapy plus treatment with Temodar® during radiation therapy, followed by an additional 6 cycles of treatment with Temodar®. Forty percent of the patients had their cancer completely removed surgically, 44% had their cancer partially removed surgically, and 16% only had a biopsy (tissue sample removed).
Results show that overall, patients who received Temodar®/radiation lived longer and were free from cancer progression longer than those treated with radiation therapy alone. Two years after treatment, patients who received Temodar® still experienced superior outcomes compared to patients that received radiation therapy alone. The average overall survival for patients was 14.6 months for those treated with Temodar®/radiation, compared to 12.1 months for those treated with radiation alone. The average progression-free survival was 7 months for those treated wtih Temodar®/radiation, compared to 5 months for those treated with radiation alone. At 2 years, the overall survival rate was 26.5% for patients treated with Temodar®/radiation, compared to 10.4% for those treated with radiation alone. Temodar® was generally very well tolerated.
Patients diagnosed with GBM may wish to speak with their physician about their individual risks and benefits of treatment with Temodar®.
1.Schering Corporation. Prescribing Information for Temodar®. Available here. Accessed March 2005.
2.Stupp R, Mason WP, van den Bent MJ, Weller M, et al. Radiotherapy plus concomitant and adjuvant temozolomide for glioblastoma. New England Journal of Medicine 2005;352:987-996.