FDA panel recommends Avastin approval for Glioblastoma
The FDA Oncologic Drugs Advisory Committee (ODAC) met yesterday and unanimously recommended that Avastin offered benefit to patients with previously untreated Glioblastoma multiforme (GBM), a fatal form of brain cancer. If accelerated approval is granted on May 5th, it will be the first new treatment for the disease in 10 years.
The American Cancer Society estimates that 21,810 malignant
tumors of the brain or spinal cord are diagnosed per year in the United States; approximately 10,000 of these are likely to be Glioblastoma. GBM has a tendency to recur and relapse is common. There are few non-surgical options available to patients, so it represents an area of high unmet medical need.
What was so compelling about the Avastin data?
According to Genentech, the non-comparative Phase II data from the BRAIN study involved 167 patients, of who 85 received treatment with Avastin in combination with irinotecan and were compared to Avastin alone in patients who had previously progressed on prior temozolomide and radiotherapy. Primary endpoints included objective response rate and progression free survival (PFS). Secondary endpoints included OS and safety.
- In 28 percent, tumors shrank to at least half their original size;
- In those whose tumors shrank, half experienced a response of at least 5.6 months;
- 43 percent lived six months without their disease getting worse; and
- Half lived at least 9.3 months after starting treatment with Avastin and 38 percent survived longer than one year."
There were no new adverse events beyond those reported in previous indications for colorectal, lung and breast cancer.
There are few available treatments for patients who have relapsed after treatment with temozolomide (Temodar). Temozolomide is approved for the first line treatment of GBM and showed significant survival of 2.5 months when used in combination with radiotherapy (RT) compared to RT alone. It makes approx. $1B in revenues annually. I'll be curious to see how the phase III frontline trial shapes out, what the comparator arm will be and how well patients do on upfront Avastin. If the phase II refractory data is anything to go by, the results may look fairly promising.
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One Response to “FDA panel recommends Avastin approval for Glioblastoma”
Having treated many GBM patients with bevacizumab (Avastin), often in combination with other drugs, it seems to have activity in glioblastoma with radiographic and clinical improvement. We need to remember how unsuccessful our prior attempts at finding drugs to benefit patients with glioblastoma have been, with most trials for recurrent glioblastoma showing little benefit, regardless of the treatment strategy.
Although the jury is still out whether we are seeing a true anti-tumor effect or some effect on blood-brain-barrier permeability (which would affect brain swelling and MRI contrast enhancement), the fact that there is ANY effect is remarkable given how aggressive this tumor is. In addition to the known risks from Avastin, there are some concerns in the neuro-oncology community that STOPPING Avastin down the road might result in a rebound of tumor growth and enhancement. There is also concern that Avastin might make the tumor more infiltrative (rather than growing as a mass) and increase the risk of seeding of the cerebrospinal fluid and the lining of the brain, a type of spread known as leptomeningeal metastasis. These concerns, however, haven’t been proven yet, and might also apply to other therapies attacking the same target as Avastin, which is known as VEGF.
Avastin is definitely NOT a magic bullet for glioblastoma, and we obviously need better treatments. But it’s still a step forward when, previously, we had been spinning our wheels for quite some time.
Jai Grewal, MD
Neuro-oncology
Long Island Brain Tumor Center
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