A decision by U.S. regulators to yank approval of a drug used to treat breast cancer is placing fresh pressure on the federal government to make a decision about the medication's future in Canada.
Avastin does not appear to delay tumour growth, prolong life or improve the quality of life for women with a form of breast cancer known as HER2 negative that has metastasized, or spread, to other parts of the body, the U.S. Food and Drug Administration ruled on Friday.
The drug can also cause side effects that are potentially fatal, including high blood pressure, bleeding, hemorrhaging, heart attack and development of perforations in the nose, stomach, intestines and other parts of the body.
"This was a difficult decision. FDA recognizes how hard it is for patients and their families to cope with metastatic breast cancer and how great a need there is for more effective treatments," FDA commissioner Margaret Hamburg said in a statement.
In Canada, the drug is available for treatment of breast cancer, as well as certain forms of colorectal, lung and brain cancer.
In a statement, the department said it is reviewing Avastin to determine whether it should remain an option for treatment of metastatic breast cancer, and will use the FDA's decision in its determination.
"No decision to revoke an authorization in respect of a marketed drug is taken lightly," the department wrote.
However, medical experts across the country say Avastin is used in only a handful of cases because most provincial formularies don't cover it. The overall impact on patients of withdrawing it from use would likely be minimal.
"There was really very modest evidence of benefit and quite a bit of toxicity," said Carol Sawka, vice-president of clinical programs and quality initiatives at Cancer Care Ontario.
Health Canada gave accelerated approval to Avastin as a breast cancer treatment in 2009 under its "notice of compliance" program, which allows the department to let a promising drug on the market before full safety and efficacy data are available.
Soon after, studies involving more patients in real-world settings began to emerge, suggesting the drug might not be as effective as first believed and caused serious side effects.
Eitan Amir, a medical oncologist at Princess Margaret and Mount Sinai hospitals in Toronto, said he expects Health Canada will eventually follow the FDA's lead and pull approval for Avastin to treat breast cancer. He added there may be some disappointment, because evidence suggests the drug may work in certain cases. The problem is determining which ones, he said.
"I think most of us would probably agree that there is likely to be some subpopulation that do benefit from it, but we don't know how to select those, and treating all women with advanced [breast]cancer with this drug probably is not the right thing to do," he said.
Roche Canada, which manufactures Avastin, said it is "disappointed" by the FDA's decision, noting that the European Medicines Agency decided to keep the drug as an option for women with metastatic breast cancer.