CHICAGO — New research raises fresh questions about which cancer patients benefit from Avastin, a drug that lost its approval for treating breast cancer nearly two years ago.
Avastin did not prolong life when used as a first treatment for people with brain tumors like the one US Senator Edward M. Kennedy died of several years ago, two studies found.
In one, patients who were expected to benefit the most from Avastin based on genetic testing had the worst survival rates. Side effects also were more common.
The drug is approved for treating brain tumors that have recurred for people who already tried chemotherapy or radiation. But that approval was based on studies suggesting it briefly delayed the worsening of the disease. No definitive study shows it helps those patients live longer, either.
Something similar happened with breast cancer: Avastin won Food and Drug Administration approval after studies suggested it delayed disease progression. But when later research showed it did not prolong life and brought more side effects, its approval for breast cancer was revoked.
However, many cancer experts say the same thing should not happen now, and that Avastin should retain its approval for brain cancer patients whose disease has recurred.
‘‘I would definitely not want the FDA to take that away from patients,’’ said Dr. Deepa Subramaniam, director of the brain tumor center at Georgetown Lombardi Comprehensive Cancer Center in Washington, D.C. ‘‘That’s very different from the breast cancer story,’’ in which there are many other drugs that can be tried, she said. She had no role in the studies, discussed Sunday at an American Society of Clinical Oncology conference.
Avastin, made by Swiss-based Roche’s Genentech unit, deprives tumors of a blood supply. It’s also sold for treating certain colon, lung, and kidney tumors. Another study discussed Sunday and released previously showed it helped women with advanced cervical cancer live nearly four months longer.
The new brain cancer studies tested it as initial treatment for glioblastoma, the most common and deadly type of tumor.
In one study, 637 patients got standard chemotherapy plus radiation; half also received Avastin. Both groups lived about 16 months, and those on Avastin had more side effects — mostly low blood counts, blood clots, and high blood pressure.
‘‘Our study would strongly suggest that it is not beneficial to do it as front-line treatment but to reserve it as second-line or salvage therapy,’’ said the study’s leader, Dr. Mark Gilbert of the University of Texas MD Anderson Cancer Center.
More troubling, independent experts said, is that patients expected to do the best based on genetic and other tests had a worse survival trend, 16 months versus 25 months for others.
New research needs to be done to define which patients benefit, said Rakesh Jain, a brain tumor expert at Massachusetts General Hospital. ‘‘We just cannot give these agents to every patient,’’ he said.
A second study that tested Avastin as initial therapy with radiation and the drug Temodar found it did not prolong life, but patients on Avastin went nearly five months longer before their tumors appeared to worsen.