The government and Genentech are warning doctors that Avastin, which is used to treat colorectal cancer, increases patients’ risk of chest pain, strokes, ministrokes, heart attacks and potentially lethal heart ailments.
A Genentech spokeswoman, Colleen Sweeney, said Friday that heart ailments had killed some patients who took the drug, but she could not say how many. Genentech, which is based in South San Francisco, Calif., developed and manufactures the drug.
During clinical trials before the drug’s approval, one patient died but a “clear relationship” could not be determined between Avastin use and the death, which was heart-related, she said. Additional analyses led to the drug warning by Genentech and the Food and Drug Administration.
“Right now, we’re working with the F.D.A., with these analyses, to update the Avastin label,” she said.
Shares in Genentech fell $2.88, or more than 6 percent, to close at $44.23 on the New York Stock Exchange, but rebounded by 49 cents in after-hours trading.
Genentech told health care providers in its warning letter that patients whose cancer had spread were twice as likely to suffer serious heart ailments if they received Avastin with their chemotherapy.
The highest-risk patients had a history of heart problems and were older than 65.