The treatment combination consisting of Avastin (bevacizumab) plus Camptosar (irinotecan) improves time to cancer progression compared to treatment with Temodar (temozolomide) in patients with newly diagnosed glioblastoma. These results were recently published in the Journal of Clinical Oncology.
Glioblastoma is an extremely aggressive form of brain cancer. Standard therapy includes surgery to remove as much of the cancer as possible, chemotherapy and/or radiation therapy. Despite treatment, however, overall survival for patients with glioblastoma remains suboptimal, indicating a significant need for improved therapeutic approaches.
A subset of glioblastoma includes cancer cells that genetically have a nonmethylated O6-methylguanine–DNA methyltransferase promotor. Researchers have been evaluating different treatment options for glioblastoma patients with this genetic subtype, as they often respond differently to treatment than other subtypes of glioblastoma.
Researchers recently conducted a clinical trial comparing two different treatment regimens in glioblastoma that had the nonmethylated O6-methylguanine–DNA methyltransferase promotor. The trial included 182 patients: one group of patients was treated with bevacizumab plus irinotecan, and the other group of patients was treated with temozolomide. Both groups also underwent radiation therapy.
Bevacizumab is an agent referred to as an antiangiogenic agent that reduces the formation of blood vessels. Since blood vessels carry blood to the cancer cells, antiangiogenic agents produce their anti-cancer effects by essentially starving cancer cells of their nourishment which they obtain from blood. Both irinotecan and temozolomide are chemotherapy agents.
- At 6 months, nearly 80% of patients treated with bevacizumab/irinotecan had not experienced progression of their cancer, compared with only 42.6% of patients treated with temozolomide.
- The median time to cancer progression was nearly 9.7 months for patients treated with bevacizumab/irinotecan, compared with approximately 6 months for those treated with temozolomide.
- Once a patient’s cancer started to progress, they were allowed to “cross-over” into the other treatment group to begin therapy with the other treatment they had not previously received.
- Quality of life was similar between the two treatment groups.
The researchers concluded that treatment with bevacizumab/irinotecan significantly improves the time to cancer progression compared to temozolomide among newly diagnosed patients with the subset of nonmethylated O6-methylguanine–DNA methyltransferase promotor glioblastoma. Due to the fact that patients could cross over and receive both treatments during the trial, differences in overall survival between the two treatment groups is difficult to accurately assess.
Reference: Herrlinger U, Schafer N, Steinbacch J, et al. Bevacizumab plus irinotecan versus temozolomide in newly diagnosed O6-methylguanine–DNA methyltransferase nonmethylated glioblastoma: the randomized GLARIS trial. Journal of Clinical Oncology. 2016; 34 (14): 1611-1619.
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