Two months after an advisory panel recommended that federal regulators withdraw Genentech’s $6 billion-a-year blockbuster Avastin for treating breast cancer, the US Food and Drug Administration (FDA) has given itself another three months before making any final decisions.

There have been serious issues with the drug, which is often a last-resort for late-stage breast cancer patients, but which has been shown to cause serious side effects, among them arterial blockage in the lungs, gastrointestinal perforation, and severe bleeding.

In November 2009, Genentech, the San Francisco-based company that makes Avastin, asked the FDA to approve an expansion of the drug’s use in treating advanced forms of breast cancer. The FDA was expected to rule on that question last Friday, but that deadline has been extended until 17 December to give the agency time to review new data submitted by the company.

Independently, back in July, an FDA advisory panel voted 12-1 in favor of revoking approval for Avastin’s use in treating advanced forms of breast cancer, based on clinical trials that showed the drug offered no added benefits and more side effects when compared to standard chemotherapy. Avastin had been approved for use in breast cancer in 2008 under an “accelerated approval” program. That initial approval went against the recommendations of another advisory committee, which voted 5-4 against Avastin’s use for breast cancer treatment in December 2007.

“During the review period, the approval status and availability of Avastin for metastatic breast cancer will not change,’’ Erica Jefferson, an FDA spokesperson, told The New York Times.

If the FDA revokes its approval for Avastin’s use in breast cancer, it can still be prescribed off-label, and will still be recommended for colon, lung, kidney and brain cancers. But off-label status would come at a price — a higher one, paid by patients. Currently estimated to cost around $100,000 a year, it’s one of the priciest cancer drugs on the market. Genentech has a program in place that limits the cost of the drug for some patients to $57,000 a year, but that price cap won’t apply for off-label prescriptions.

Some see political implications at the heart of pushing the decision past the US midterm elections in November. Because Avastin is so expensive, and only treats breast cancer, rather than curing it, many critiques of the drug have centered around its costliness versus its clinical value. But these arguments have been cast in a new light after the passage of the US health care reform bill.

At the FDA advisory committee vote in July, one of the panel members, Jean Grem, a professor of medicine at the University of Nebraska Medical Center, explained her vote against Avastin, saying: “I don’t think a median progression-free survival of .9 months is clinically meaningful. And the toxicities can be substantial. We aren’t supposed to talk about cost, but that’s another issue”.

A Wall Street Journal opinion piece featured that last sentence alone, and many opponents of the Obama-backed health care reform seized upon Grem’s discussion of cost as an admission that the FDA was now “rationing” medications. Glenn Beck, the Fox News commentator, characterized the FDA advisory panel’s Avastin vote in July as the first instance of rationing by the so-called “death panels” that had been predicted by conservative commentators.