The Food and Drug Administration said on Thursday that it would move to revoke approval of the widely used drug Avastin as a treatment for breast cancer, saying the drug was not effective in helping patients.
The decision, which is rare for the F.D.A., has been anticipated since July, when an F.D.A. advisory committee voted 12 to 1 in favor of rescinding approval.
The F.D.A. said its recommendation was the start of a process, and that for now, the approval for breast cancer will remain in place and patient access to the drug should not be immediately affected. Genentech, the drug’s manufacturer, will have 15 days to request a hearing. It is expected to do so.