WASHINGTON – The Food and Drug Administration has approved a new Pfizer drug for a subset of lung cancer patients with a particular genetic mutation.

The twice-a-day pill, called Xalkori, is part of a new wave of personalized medications that fight disease by targeting specific genes found in certain patients.

Last week, the FDA approved another drug that uses similar gene targeting technology to treat two rare forms of lymph node cancer.

Xalkori is approved to treat a small subset of non-small cell lung cancer patients, less than 7 percent, who have an abnormal gene that stimulates cancer cells and causes tumor growth. It works by blocking proteins produced by the gene.

“It’s another example of how we’re using molecular medicine to subtype lung cancer into more specific and treatable diseases,” said Dr. Roy Herbst, a lung cancer expert who is chief of medical oncology at Yale University.

Including previously approved targeted therapies, “we have specific therapies now that we can offer for about 18 percent of lung cancer patients that are far superior to chemotherapy and that in many cases can cause their tumors to melt away with few side effects,” Herbst said.

The FDA said it also approved a genetic test to screen for the mutation, known as an abnormal anaplastic lymphoma kinase gene. The test is made by Abbott Laboratories.