WASHINGTON (AP) -- The Food and Drug Administration expanded approval of a Pfizer drug to treat a small subset of lung cancer patients with a rare mutation.
The agency said Friday that Xalkori capsules are now approved for patients with the ROS-1 gene mutation, who make up about 1 percent of U.S. patients with non-small cell lung cancer, the most common form of the disease.
The twice-a-day drug is part of a new generation of medications that fight disease by targeting specific genes found in certain patients. It was initially approved in 2011 for another subset of lung cancer patients who have an abnormal gene that stimulates tumor growth.
The drug blocks certain proteins found in tumors with genetic mutations, with the aim of slowing the spread of cancer.
"Lung cancer is difficult to treat, in part, because patients have different mutations, some of which are rare," said Dr. Richard Pazdur, FDA's director for cancer drugs, in a statement. "The expanded use of Xalkori will provide a valuable treatment option for patients with the rare and difficult to treat ROS-1 gene mutation."
Like most new cancer drugs, Xalkori carries a hefty price tag: $14,336 per month, or about $172,000 per year. That number does not take into account discounts and rebates often negotiated by insurers. Pfizer posted sales for the drug of $488 million in 2015, according its annual report.
The FDA approved the new indication based on a study in 50 patients in which 66 percent of patients saw their tumor shrink partially or completely. That benefit lasted about 18 months for the typical patient.
The most common side effects of Xalkori include vision disorders, nausea, swelling, diarrhea and inflammation.
About 188,000, or 85 percent, of the 221,000 lung cancer cases diagnosed each year are non-small cell lung cancer. Roughly three-fourths of patients aren't diagnosed until tumors have spread, which dramatically reduces their life expectancy.
Shares of New York-based Pfizer Inc. rose 90 cents, or 3 percent, to close at $30.49.