By Anna Yukhananov
WASHINGTON (Reuters) - Pfizer's Inlyta drug for patients with advanced kidney cancer got the nod from U.S. regulators on Friday, boosting the company's plans to offset plunging Lipitor sales.
The Food and Drug Administration said the drug, known generically as axitinib, was effective at treating patients who did 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 are expected to die from the disease, according to the American Cancer Society.
About 20 percent to 30 percent of these patients have advanced disease at the time of diagnosis, Pfizer said.
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.
Shares of Pfizer dipped 0.6 percent to $21.51 in afternoon trading on the New York Stock Exchange, 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 previously approved treatments, such as Nexavar, which is 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 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 people 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.
U.S. patients rarely use cytokines, such as interferon, and are far more likely to be given Sutent as an initial treatment option, 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)
