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 says 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 wave 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 a gene that stimulates tumor growth.
The drug blocks certain proteins found in tumors with genetic mutations, with the aim of slowing cancer spread.
Xalkori posted sales of $438 million in 2014.