Shares in Roche have fallen this morning after advisors to the US Food and Drug Administration recommended that the firm’s oncology blockbuster should no longer be approved as a treatment for breast cancer.

The FDA’s Oncologic Drugs Advisory Committee has voted 12 to one that use of Avastin (bevacizumab) in combination with paclitaxel for previously-untreated (first-line) advanced HER2-negative breast cancer be removed from the drug’s US label. Avastin received a conditional thumbs-up in 2008 for the aforementioned indication under the FDA’s accelerated approval programme, a decision which saw the agency reject advice from its panellists.

That approval was reliant on data from follow-up studies and Roche’s Genentech unit submitted two supplemental Biologics License Applications in November. One was based on the Phase III AVADO study that investigated the drug in combination with docetaxel and the other came from data produced by the late-stage RIBBON-1 trial evaluating Avastin in combination with a taxane or anthracycline-based chemotherapy or Roche’s own oral chemotherapy, Xeloda (capecitabine).

Both studies met their primary endpoints of improving the time women lived without the disease worsening, Roche noted at the time of filing. However the FDA panel is not impressed.

The ODAC also voted 13-0 that the AVADO study failed to prove that the risks and adverse effect profile associated with use of Avastin in combination with docetaxel did not outweigh its benefits in this patient cohort and voted 12-1 against the same question in regards to the drug in combination with other chemotherapies.

Breast cancer patients on Avastin did not show significant improvement in lifespan (a median of 2.9 months) despite earlier studies suggesting that the cancer progression would be delayed by 5.5 months, the advisers said. Reported side-effects included high blood pressure and abnormal levels of white blood cells.

Sandra Horning, global head of clinical development haematology/oncology at Genentech, said “we are disappointed by the committee's recommendation and believe Avastin should continue to be an option for women with this incurable disease”. She added that “we will continue to discuss the data from the more than 2,400 women who participated in three Phase III studies with the FDA”.

The agency is expected to make a decision on the first-line use of Avastin for advanced breast cancer by September 17, but analysts feel it is a foregone conclusion given the scale of the panel’s rejection. Tim Anderson at Sanford Bernstein said that worldwide Avastin sales are expected to reach $6.5 billion this year, and that includes about $1.2 billion from breast cancer. Eliminating US breast cancer sales may cut Roche’s earnings per share by about 5%, he added.

Investors seem concerned as well and at 10.30am (UK time), Roche’s shares were down 4% at 137.20 Swiss francs.