WASHINGTON - A panel of government experts said Wednesday that Genentech's cancer drug should not be approved for expanded use in breast-cancer patients.
The Food and Drug Administration's advisers voted 5 to 4 against the new use, on grounds that the benefits of the treatment did not outweigh potential risks. The agency does not have to follow the advice of its panel, though it usually does.
Initially approved in 2004 to treat colon cancer, Avastin was the first drug to fight cancer by stopping nutrients from reaching tumors. Such "targeted therapies" were thought to hold promise for eliminating chemotherapy, but that promise remains unmet.
South San Francisco-based Genentech Inc. asked the FDA to approve the drug for use alongside chemotherapy in patients with advanced breast cancer who have not already taken other drugs. While some doctors already use the drug to treat breast cancer, FDA approval would have increased the practice significantly.
Avastin, which is also approved to treat types of lung cancer, was the company's second best-selling product last year with sales of US$1.7 billion.
"We are disappointed by the split vote of the advisory committee," Susan Desmond-Hellmann, Genentech's head of product development, said in a statement. "We believe that Avastin can help meet a significant unmet medical need for women with metastatic breast cancer."
Prior to the meeting, FDA scientists said that while Avastin slowed the progression of cancer, it did not improve patients' life span overall. Patients on Avastin and chemotherapy survived on average 26.5 months, compared with 24.8 months for patients taking just chemotherapy. FDA said the difference was not significant.
Scientists also questioned the drug's safety. Patients on Avastin had 20 percent higher toxicity levels than those on chemotherapy. Common side effects included hypertension and blood clots.
The panel's decision has implications for all drug makers working on cancer therapies. Increasingly, the FDA wants to see overall survival rates improve -- not just the delay of cancer's progression -- before it grants U.S. approval.
Avastin, long a recipient of superstar treatment and heavy touting in the Genentech portfolio, has also got the attention of increasingly competitive rivals. Earlier in the year, Britain's GlaxoSmithKline received approval for Tykerb to treat patients with advanced breast cancer.
The FDA is scheduled to make its final decision on Avastin in February.
While most analysts leaned against an approval decision for the drug Wednesday, Morgan Stanley's Steven Harr suggested FDA could show some leeway given the narrow panel vote. Harr also pointed out that of the five cancer specialists on the panel, four favored approval.
Shares of Genentech fell $6.14, or 8.4 per cent, to $66.64 in regular trading Wednesday. They fell another 13 cents in after-hours trading.
