Treatment with the cancer drug Avastin may affect fertility in some women, the Food and Drug Administration (FDA) said Tuesday. The agency said a new warning about the risk of “ovarian failure” was added to the drug’s label.
The FDA further advised doctors to counsel women of child-bearing age about the possibility that taking Avastin could potentially cause ovaries to stop releasing eggs early.
The data on ovarian failure came from a clinical trial involving 179 women with colon cancer who were being treated with chemotherapy. About half the women received Avastin (bevacizumab) in addition to chemotherapy. The study showed that 34% of women in the Avastin group experienced ovarian failure, compared with 2% of patients receiving chemotherapy alone.
Ovarian function returned in about 20% of the women after Avastin was stopped, but the long-term effects of the drug on fertility remain unknown, the FDA said.
Avastin is currently approved to treat certain types of lung, brain, kidney, colon and breast cancers, but late last year, an FDA advisory committee recommended that Avastin’s approval for breast cancer be rescinded. That unanimous recommendation was based on evidence from four clinical trials showing that the drug failed to extend the lives of metastatic breast cancer patients. It did appear to delay the progression of the disease by one to three months, however, but at the cost of serious and potentially life-threatening side effects.
MORE: FDA Recommends Withdrawing Avastin’s Approval for Breast Cancer
The new update of Avastin’s warning label is separate from the debate over its breast cancer approval. The agency’s commissioner, Dr. Margaret A. Hamburg, has yet to make a final decision on whether to revoke its approval.
Meanwhile, Blue Shield of California announced that it would no longer pay for use of the drug to treat breast cancer. With 3.2 million members, Blue Shield may be the largest insurer to end such payments. Reported the New York Times:
Because it is an emotional and politically contentious issue, with some women saying the drug is keeping them alive, many insurers have said they will wait until a final decision from the F.D.A. before re-evaluating their coverage policies. And Medicare has indicated it will continue paying for the drug even if the F.D.A. revokes the approval.
But Blue Shield decided not to wait. In a note posted on its Web site, it said reimbursement would end Oct. 17, though “exceptions may be considered on a case-by-case basis.”
“We agreed with the F.D.A. panel,” Stephen M. Shivinsky, a spokesman for Blue Shield, said on Friday. He said the insurer would continue to pay for the drug for women who were already using it.
Regardless of whether the drug retains its approval for the treatment of breast cancer, it will remain on the market to treat other cancers for which it is approved. It is currently the best-selling cancer drug, with annual sales of about $7 billion.
MORE: Medicare Will Continue to Pay for Avastin for Breast Cancer
Meredith Melnick is a reporter at TIME. Find her on Twitter at @MeredithCM. You can also continue the discussion on TIME’s Facebook page and on Twitter at @TIME.