Avastin: Mixed Results Against Different Cancers
Drug improved survival by 4 months with cervical cancer, but no such benefit seen with brain tumors
"We feel with this study, we've shown this drug can improve survival," said Tewari, a gynecologic oncologist at the University of California, Irvine, Medical Center. "If we're preserving their lives so future therapies may be able to confer some benefits, we have the potential to turn this disease into a chronic disease."
The two drug trials involving glioblastoma followed up on earlier research that showed Avastin might be useful in treating recurring brain tumors.
Given that success, researchers wanted to see if the drug could serve as a first-line therapy that could be used with standard radiation and chemotherapy to treat newly diagnosed glioblastoma, said Dr. Mark Gilbert, lead author of one of the trials.
The trials found no survival benefit in using Avastin on newly diagnosed glioblastoma patients, however. The U.S. National Cancer Institute sponsored one trial, while the other was sponsored by the drug's manufacturer, Roche.
"We were surprised that we did not see a significant patient benefit," said Gilbert, a neuro-oncologist at the M.D. Anderson Cancer Center.
Gilbert speculated that Avastin might not be as useful in treating new tumors because standard therapy calls for surgical removal of the cancer prior to chemotherapy. In his trial, more than 60 percent of patients had their tumors completely removed, and another 30 percent had most of the cancer removed, he noted.
With the tumors gone, Avastin may not have been as effective in preventing blood vessel growth to cancer cells, he said.
The drug still could prove useful in treating new glioblastoma patients whose tumors cannot be surgically removed due to their location in the brain, he suggested.
"In that scenario, is there a role? The answer is, don't know, but it's certainly worth asking," Gilbert said.
He added that patients taking Avastin alongside chemotherapy also showed increased symptoms, worse quality of life and a decline in their ability to think and reason. Doctors can't tell whether these are side effects of the drug or an indication that the cancer continued to progress but the growth was cloaked by Avastin's ability to restrict blood vessel development, Gilbert said.