In the arm studying Avastin with CPT-11, 37.8 percent of patients responded to the treatment, while 50.3 percent surpassed the six month progression-free survival mark. Overall survival was 8.7 months, a little less than the Avastin only study.
Cloughesy believes the study shows the apparent power of Avastin when used alone in treating deadly brain cancers for which few effective treatments now exist.
"I think what this tells us is that the majority of the effects we're seeing are due to the Avastin," he said.
In addition, Avastin was well tolerated. While some serious side effects were noted -- brain hemorrhage, strokes and heart attacks -- they were seen in a very small number of patients. Avastin also appeared to reduce brain swelling, allowing patients to significantly lower the steroid dose they had to take, eliminating a number of debilitating side effects.
"Because their brain swelling went down and they could lower their doses of steroids, some patients saw a marked improvement in function," Cloughesy said.
About 20,000 patients will be diagnosed with glioblastoma this year, of those 14,000 will die. Senator Ted Kennedy died of the disease August 25.
The last new systemic therapy for recurrent glioblastoma was approved in 1976. Until Avastin, all other experimental therapies tested in this type of cancer failed to meet the FDA guidelines for approval. It's vital that less toxic, more effective therapies are found to fight glioblastoma, Cloughesy said, both when it recurs and when it is first diagnosed. Studies are underway now to see if the study results can be validated in patients with newly diagnosed glioblastomas.
A significant study finding was that Avastin was nearly as effective alone as it was when given with chemotherapy, but was much better tolerated. In consultation with their doctor, a patient facing less than a year to live might opt for Avastin alone to promote better quality of life and avoid the toxic side effects of chemotherapy.
Avastin is an angiogenesis inhibitor, meaning it cuts off the independent blood supply that a tumor develops to feed and oxygenate itself. A molecularly targeted therapy, Avastin neutralizes vascular endothelial growth factor (VEGF), a chemical signal that stimulates the growth of new blood vessels, or angiogenesis. In addition to recurrent glioblastoma, Avastin has been approved for use in metastatic colorectal, breast and kidney cancers as well as non-small cell lung cancer.
In addition to UCLA's Jonsson Cancer Center, other institutions participating in the study included the University of California, San Francisco, M.D. Anderson, Dana Farber, Memorial Sloan-Kettering, Duke University, Henry Ford Hospital, the University of Virginia, the University of Chicago, Evanston Northwestern Healthcare, and the University of Utah Hospital. The study was funded by Genentech, which manufacturers Avastin.
UCLA's Jonsson Comprehensive Cancer Center has more than 240 researchers and clinicians engaged in disease research, prevention, detection, control, treatment and education. One of the nation's largest comprehensive cancer centers, the Jonsson center is dedicated to promoting research and translating basic science into leading-edge clinical studies. In July 2009, the Jonsson Cancer Center was named among the top 12 cancer centers nationwide by U.S. News & World Report, a ranking it has held for 10 consecutive years. For more information on the Jonsson Cancer Center, visit our website at http://www.cancer.ucla.edu.
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