The Food and Drug Administration on Friday said the drug, known generically as axitinib, is effective at treating patients who do not respond to another drug for kidney cancer.

Advanced kidney cancer starts in the lining of the kidney's small tubes. Inlyta works by blocking certain receptors that can influence tumor growth.

The FDA said Inlyta is the seventh drug approved to treat advanced kidney cancer since 2005.

"Collectively, this unprecedented level of drug development within this time period has significantly altered the treatment paradigm of metastatic kidney cancer, and offers patients multiple treatment options," said Richard Pazdur, director of the FDA's office of oncology products, in a statement.

About 61,000 Americans were diagnosed with kidney cancer last year, and about one in five of them is 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.

AFTER LIPITOR

The drug is one of several new medicines Pfizer is banking on to help replace lost revenue from its cholesterol fighter, Lipitor. The world's top-selling drug began facing generic competition late last year.

"This announcement is welcome news for Pfizer as investors have long waited for signs of revival of (research) productivity," Barclays Capital analyst Tony Butler said in a note.

Last month, Pfizer also won approval to sell its Prevnar pneumonia vaccine to older adults, and not just children. The expanded population could generate more than $1.5 billion in sales.

But with six other drugs for advanced kidney cancer already sold in the United States, analysts said Pfizer will struggle to gain market share. Butler sees peak sales for Inlyta at $600 million.

Pfizer said the average monthly cost of Inlyta is less than $8,900, which is generally consistent with other drugs approved for advanced kidney cancer.

Shares of Pfizer closed 0.7 percent lower at $21.48 on the New York Stock Exchange on Friday, in line with a fall in the wider Arca Pharmaceuticals Index.

An FDA advisory committee backed the oral drug in December and said it was as safe and effective as Nexavar, a kidney cancer treatment sold by Bayer AG and Onyx Pharmaceuticals Inc.

"This was the first head-to-head trial of two targeted agents in kidney cancer," said Dr. Subramanian Hariharan, global medical lead on Inlyta at Pfizer. "Inlyta now offers a new option for patients."

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

FIRST DRUG MATTERS

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

U.S. patients rarely use cytokines, such as interferon, and are far more likely to be given Sutent as an initial treatment, the FDA has said.

Most FDA advisers said the medicine was not a significant advance over other treatments. But they said it had different side effects than other drugs for the disease, which could be important for patients who cannot tolerate older treatments.

The most common side effects with Inlyta included diarrhea, high blood pressure, loss of voice, weight loss and vomiting. Some patients also had bleeding problems, which in some cases were fatal.

The FDA said patients with high blood pressure should make sure it is under control before taking Inlyta, and those with untreated brain tumors or intestinal bleeding should not take the drug.

Inlyta is awaiting an approval decision in Europe for use in patients who were not helped by prior treatment.

Pfizer is also testing Inlyta in another late-stage trial for kidney cancer as both an initial treatment option and in previously treated patients. The company is also testing the drug as a treatment for liver cancer.

(Reporting by Anna Yukhananov in Washington and Anand Basu in Bangalore; Editing by Steve Orlofsky and Matthew Lewis)

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