An FDA panel voted on June 29 that bevacizumab (Avastin ®) in combination with paclitaxel should no longer be approved for treatment of metastatic HER2-negative breast cancer. The recommendation was unanimous, and represented the panel's second vote on the issue.

Bevacizumab - a genetically engineered drug that inhibit the growth of a network of blood vessels that supply nutrients and oxygen to tumours - was originally licensed by the FDA in 2004 for first line treatment of patients with metastatic colorectal cancer.

In February 2008, the FDA granted accelerated approval for the use of bevacizumab combined with paclitaxel for first-line treatment of chemotherapy-naive patients with metastatic HER-2–negative breast cancer. Approval was based on the E2100 trial, an open-label randomized, multicentre trial which showed that patients treated with paclitaxel plus bevacizumab had a progression free survival (PFS) of 11.3 months versus 5.8 months for those treated with paclitaxel alone.

But in August 2010, the FDA's Oncologic Drugs Advisory Committee first voted to remove bevacizumab's indication as a first-line therapy for metastatic breast cancer after Genentech's follow-up studies, AVADO and RIBBON-1, had not demonstrated that bevacizumab was associated with extended overall survival or improved quality of life. Furthermore, there were concerns that at the end of treatment the side effects of hypertension and proteinuria did not resolve in all patients, and since at least half of patients receiving initial treatment for metastatic breast cancer can expect to live for several years risks were not considered acceptable.

The FDA advisory panel's decision now goes to FDA Commissioner Margaret Hamburg, who will address the issue after the period for public comments closes at the end of July. But even if she revokes bevacizumab's use as a breast cancer drug, oncologists will still have the option of prescribing it "off label". Insurers, however, may prove less willing to fund the drug, which can cost $88,000 a year for a typical breast cancer patient.