FDA panel backs Pfizer's drug for kidney cancer

SILVER SPRING, Maryland Wed Dec 7, 2011 2:47pm EST

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SILVER SPRING, Maryland (Reuters) - Pfizer Inc won unanimous expert backing for its Inlyta experimental drug for patients with advanced kidney cancer.

A Food and Drug Administration advisory committee voted 13-0 on Wednesday that the drug, also called axitinib, had a favorable benefit-risk profile for such patients after initial treatment has failed.

The FDA, which usually approves products that win support from its advisory panels, is due to make a final decision in the first half of 2012.

Panelists said the oral drug was at least as safe and effective as previously-approved treatments, such as Nexavar, which is sold by Bayer AG and Onyx Pharmaceuticals Inc.

It also had different side effects than other drugs for the disease, which could be important for patients who cannot tolerate older treatments, said Dr. Wyndham Wilson, chair of the panel and chief of the lymphoma therapeutics section at the National Cancer Institute.

"It's my take that the toxicity profile is different, there's benefit there, and it's not inferior to currently approved TKIs," Dr. Wilson said, referring to drugs in the same class.

"If you have two drugs that are equivalently effective, ... different toxicity profiles can be very useful for the individual," he said.

About 61,000 Americans will be diagnosed with kidney cancer this year, and about one in five of them are expected to die from the disease, according to the American Cancer Society.

About 20 to 30 percent of these patients have advanced disease at the time of diagnosis, Pfizer said.

U.S. DIFFERENCE

FDA staff said Pfizer's kidney cancer drug showed the same degree of liver enzyme elevation and potential for liver failure as some other drugs in its class, but had lower rates of skin related side effects and anemia than Nexavar in a clinical trial.

However, in review documents released on Monday, FDA staff expressed concern Inlyta appeared to work better in patients previously treated with cytokines, which are rarely used in the United States.

U.S. kidney cancer patients are far more likely to be given Pfizer's Sutent as an initial treatment option rather than cytokines.

Overall, in Pfizer's clinical trial, Inlyta slowed down the progression of cancer by two months compared to Nexavar for patients who had already been treated for advanced kidney cancer, or renal cell carcinoma.

But the findings differed depending on which particular drug patients took beforehand. For patients who initially took Pfizer's Sutent, Inlyta slowed the disease by only 1.4 months, versus 5.6 months in patients previously treated with cytokines.

Based on the data, panel members said Inlyta was not a significant advance over previous treatments.

"I voted yes reluctantly," said panel member Dr. Mikkael Sekeres, from the department of hematologic oncology at the Cleveland Clinic.

"It moves the ball forward for renal cell carcinoma but it certainly didn't score a touchdown; it probably didn't even make a first down," he said of Pfizer's drug.

Inlyta, which inhibits certain receptors that can influence tumor growth and progression of cancer, is one of several new drugs Pfizer is banking on to help replace lost revenue from its top-selling cholesterol fighter, Lipitor, which began facing generic competition last week.

Pfizer shares were up 1.5 percent at $20.53 in early afternoon trading on the New York Stock Exchange, slightly outperforming the wider Arca Pharmaceutical Index.

Inlyta is awaiting an approval decision in Europe for use in patients who failed to be helped by prior treatment.

The drug is also being tested in another late-stage trial for kidney cancer as both an initial treatment option and in previously treated patients. It is also being tested as a treatment for liver cancer.

(Reporting By Anna Yukhananov, Editing by Tim Dobbyn, Bernard Orr)

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