The breast cancer guideline committee of a national organization representing leading cancer treatment centers, the National Comprehensive Cancer Network (NCCN) voted 24-0 with one abstention to stand by its existing recommendation that the antiangiogenic drug “bevacizumab in combination with paclitaxel is an appropriate therapeutic option for metastatic breast cancer.” Bevacizumab (Avastin) was the first angiogenesis inhibitor—a drug that blocks the growth of blood vessels that feed tumors—to be approved for cancer therapy.
The NCCN breast cancer panel noted that the benefits observed with bevacizumab appears to vary according to the cytotoxic agent used with it and that weekly paclitaxel seemed to provide the best results. The NCCN’s recommendations are in disagreement with a U.S. FDA advisory panel regarding clinical trial follow-up data. The FDA initially approved bevacizumab for metastatic breast cancer in 2008 under its accelerated drug approval program after results from a landmark clinical study showed that it slowed tumor progression by 5.5 months. But based on two subsequent studies, an FDA advisory panel made a recommendation last December and the FDA oncology panel last month voted to modify the product labeling of bevacizumab (remove the metastatic breast cancer indication). Patient survivors and many advocacy groups have argued that the drug does provide benefit, even if not as great as the initial study, and Genentech, which manufactures bevacizumab, has noted that it is completing a new clinical trial that pairs bevacizumab with the chemotherapy drug paclitaxel.
Even if the labeling for breast cancer is revoked, oncologists would still be able to use the drug “off-label” to treat their breast cancer patients. Insurance companies would then make their own determination whether to pay for it. How the NCCN decision will influence use of bevacizumab in breast cancer remains to be seen, but the organization’s guidelines carry weight with third-party payers. In addition, patients will also still be able to access bevacizumab and other antiangiogenic agents through clinical studies (see Science of Cancers).