US drug regulators have rescinded approval of a breast cancer drug, saying it is not effective enough to justify the risks of taking it.
The drug, Avastin, was approved for US use in 2008, but UK officials have also rejected claims that it prolongs life.
Further research showed it did not help patients live longer or improve quality of life, Food and Drug Administration commissioner Margaret Hamburg said.
Avastin will still be used to treat other kinds of cancer.
The drug is used to treat breast cancer that has spread to other parts of the body. It works by starving cancer cells of a blood supply.
However, its side-effects include severe high blood pressure, massive bleeding, heart attack or heart failure and tears in the stomach and intestines, FDA studies have found.
FDA approval of the drug had initially been given under a special programme that allows patients to start using promising treatments while the manufacturer finishes the studies to prove the medicine works as well as expected.
The decision to withdraw the approval – which can happen if results of the research do not match predictions – was not easy, the FDA said.