Genentech announced it is seeking accelerated FDA approval for Avastin (bevacizumab) as a treatment for glioblastoma. This action follows promising Phase II clinical trial results, potentially offering a new option for a condition with limited effective treatments. Glioblastoma, the most common type of brain tumor, affects 2-3 people per 100,000 annually in North America and Europe.
Clinical Trial Results and Mechanism of Action
In Phase II clinical trials involving 167 patients, 43% showed no increase in tumor size after six months of Avastin treatment. Furthermore, 28% of patients experienced a reduction of at least 50% in the size of existing tumors. Avastin functions by inhibiting angiogenesis, the process by which tumors develop new blood vessels to support their rapid growth and spread. This mechanism is particularly relevant in glioblastoma, where rapid vascularization is a hallmark of the disease.
The Need for New Glioblastoma Treatments
"There has been no substantial improvement in the treatment of glioblastoma in more than 20 years," stated Dr. Hal Barron, chief medical officer for Genentech. Glioblastoma is an aggressive and incurable condition, with a median survival time of less than one year and only about 5% of patients surviving for five years. The current standard of care provides limited benefit, underscoring the urgent need for innovative therapeutic approaches.
Avastin's Potential and Considerations
Avastin is already approved for treating lung, colon, and breast cancers. Side effects associated with Avastin include hypertension, convulsion, intestinal perforation, and slow wound healing. The Phase II trial reported two patient deaths related to these side effects; however, the overall study results indicated a significantly longer average life expectancy compared to typical glioblastoma patients. Phase III clinical trials are scheduled to begin early next year to evaluate Avastin in combination with chemotherapy and radiation.
Market Context
Approximately 19,000 primary brain tumors are diagnosed annually in the United States, with gliomas, including glioblastoma, accounting for 60% of these cases. The cost of a single course of Avastin treatment is approximately US$40,000. Genentech's stock price saw a slight increase following the announcement. Other companies, such as Pfizer and Myriad Genetics, are also developing treatments for glioblastoma and other brain tumors.
