FDA questions Roche’s Avastin for breast cancer

By Dow Jones Newswires
Posted July 16, 2010 at 10:15 a.m.

The Food and Drug Administration questioned the benefit of using Roche Holding AG’s  top-selling cancer drug, Avastin, in breast cancer.

The agency said the magnitude of an improvement seen among women being treated with chemotherapy drugs plus Avastin compared with women being given chemotherapy alone “is not clinically meaningful.” The agency also said there were more serious side effects such as bleeding seen among women being given Avastin.

The agency said the “risk-benefit ratio of (Avastin)  when added to the standard chemotherapeutic regimens … may not be considered favorable.”

The FDA posted background material to its Web site Friday before its oncology drugs advisory committee meeting Tuesday that will discuss Avastin. The agency could decide to remove the breast-cancer indication for Avastin, though the FDA didn’t specifically state it was considering that.

Avastin is approved to treat several types of cancer, including colon, lung and kidney cancer, and had global sales of nearly $6 billion last year. Analysts estimate if the breast cancer indication were to be removed that it could cut about $1 billion off annual sales.

The FDA approved Avastin to treat the most common type of advanced breast cancer in 2008 in combination with the chemotherapy drug paclitaxel under a mechanism known as accelerated approval. That mechanism allows the drugs to be approved based on initial positive studies. Companies then have to submit additional data to gain full approval. At the time the FDA went against the advice of a panel that voted 5-4 against recommending approval.

The main study that supported Avastin’s accelerated approval showed adding the drug to paclitaxel added 5 1/2 months to median progression-free survival, or the average amount of time patients lived without the cancer getting worse. The study didn’t show a statistically significant increase in overall survival.

As required, Roche then conducted two additional studies and submitted them to the FDA for full approval of Avastin. Roche is also seeking expanded approval of the product for use in combination with other types of chemotherapy drugs.

The FDA said the two studies “failed to confirm the magnitude” of the benefit seen in the first study that supported Avastin’s approval. One study showed women lived less than a month longer without their disease progressing compared with women not receiving the drug as part of their treatment, while the other study showed a difference of no more than 2.9 months, the FDA said.

Roche, in a background document also posted to FDA’s site, said the studies show Avastin is “safe and effective” when added to chemotherapy to treat breast cancer.

The two new studies will be reviewed Tuesday by the FDA oncology drug advisory committee. The FDA didn’t release the list of questions set for discussion, simply saying it was seeking committee advice on “whether clinical benefit has been demonstrated.” The FDA could decide to grant full approval of Avastin as well allow its use in combination with other chemotherapy drugs. That decision is expected by September and the panel’s advice on whether it thinks Avastin has benefit in breast cancer will be taken into consideration.

Avastin is designed to inhibit tumors by interfering with a protein that forms blood vessels in the tumors. Chemotherapy is an older, standard treatment for cancer that kills cancer cells, but it also kills healthy cells throughout the body.

Avastin is usually given in combination with chemotherapy drugs.

Last month, Pfizer Inc.  said it would withdraw a cancer drug Mylotarg by October after it had been approved in 2000 as part of FDA’s accelerated-approval program. The drug, marketed by Wyeth until Pfizer bought the company, was approved for patients 60 and older with a type of acute myeloid leukemia. However, the follow-up clinical study showed the drug wasn’t effective and had more safety problems.

Mylotarg is the only drug approved under the accelerated approval mechanism that will be removed from the market.

In 2005, the FDA restricted the use of AstraZeneca PLC’S lung cancer drug Iressa to a certain group of patients after a clinical study showed it didn’t prolong survival.

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