An advisory panel to the US Food and Drug Administration has ruled that the cancer drug Avastin (bevacizumab) should not be approved for the treatment of advanced breast cancer. Shares in Genentech, the California-based biotechnology company that makes the drug, fell by $10 to $66 as news of the decision emerged last week. European regulators approved the drug for breast cancer use earlier in the year, but the FDA panel heard that although the drug helped some patients there was insufficient evidence that it improved their long-term survival prospects, and voted 5?4 against its approval.