Avastin: Mixed Results Against Different Cancers
Drug improved survival by 4 months with cervical cancer, but no such benefit seen with brain tumors
Given that cervical cancer is preventable through pap smears and HPV vaccination, Dizon questioned whether such an expensive drug would be affordable for women who couldn't afford the basic preventive medicine that could have kept the cancer from occurring in the first place.
"If you can't afford screening with pap smears, it's unlikely you'll be able to provide women bevacizumab as treatment," he said.
Avastin also increased the risk of troubling side effects, including high blood pressure, thromboembolisms [clots in blood vessels] and holes in the gut called fistulas.
Lead author Dr. Krishnansu Tewari noted that these side effects did not include death, and contended that the increase in side effect risk was moderate and acceptable.
"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.