FDA may reject Avastin for breast cancer

Shares in Roche's majority-owned US biotech Genentech plummeted almost nine per cent on 5 December after a panel of medical experts recommended that the FDA deny approval of Avastin (bevacizumab) for the treatment of breast cancer.

The advisor panel to the FDA voted 5-4 against expanding the approved use for Genentech's best-selling drug to include breast cancer patients. The reason? The drug did not significantly lengthen the lives of women who took it alongside chemotherapy.

While the panel did not strictly advise the panel to reject Avastin, they said the benefits of the drug had to be weighed against an increased risk of side effects, including heart attacks. The deaths of six patients have been attributed to the drug, which is equivalent to 1.7 per cent of the 363 clinical trial subjects.

Avastin has been approved to treat certain colon and lung cancers, where it can add months to patients' lives. In a breast cancer trial, however, its benefit was limited to a delay in the spread of the disease. It also put patients at risk for serious side effects.

Before the clinical trial, analysts had reported that Genentech could rack up sales of over USD 1bn in additional sales, if the FDA endorsed its use in breast cancer. The FDA is not obliged to obey any recommendation made by advisory panels, but in practice it usually does. A decision regarding Avastin's is expected toward the end of February 2008.

Genentech has come out fighting saying it believes that Avastin can help meet a significant unmet medical need for women with metastatic breast cancer. But FDA insiders and external critics said the clinical trial did not prove that patients experienced an increased quality of life through taking Avastin.

Cost is also an important issue for the FDA. Had the drug been approved as a first-line treatment of patients with metastatic breast cancer, a single course would cost approximately USD 84,700. Genentech says it supports patient assistance programmes to cover some of the cost for patients with annual incomes under USD 100,000.

All is not lost, however. Two other trials of Avastin in metastatic breast cancer are under way, with results expected in H2 2008. The drug also is being tested in kidney cancer, brain cancer and other cancers.

In FY06, Genentech posted sales of USD 1.7bn for Avastin in the US; its Swiss-based parent company Roche sells the drug in other markets.