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. Two weeks ago, 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 seven 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.
About 187,000, or 85 percent, of the 220,000 lung cancer cases diagnosed each year are non-small cell lung cancer. Roughly three-fourths of patients aren't diagnosed until tumors have spread and only six percent of those patients live five years.
“It's pretty exciting,” said Dr. David Carbone, a lung cancer specialist at Vanderbilt University, one of the sites that tested the drug. Only a small share of lung cancer patients have the gene mutation this drug targets “but for those people it makes a huge difference,” he said.
Analysts predict Xalkori could be a blockbuster product for Pfizer, eventually reaping more than $2 billion in annual sales by 2021.
The FDA approved the drug under its accelerated approval program which speeds up the clearance of therapies that show promising early results.
Pfizer released follow-up data on the drug in June, reporting that 88 percent of patients in one study saw their tumors shrink at least somewhat after one year on Xalkori. In a second study, 54 percent of patients had their tumors shrink by about a third or more and 83 percent had tumors shrink somewhat. Most patients had only mild side effects, but two of the nine patient deaths during that study were considered treatment-related.
The most common side effects of the drug include vision disorders, nausea, diarrhea and inflammation.
The FDA's accelerated approval program has come under criticism in the last year after follow-up studies showed the best-selling cancer drug Avastin did not extend the lives of patients with breast cancer. The FDA granted the drug accelerated approval because a single study suggested it slowed tumor growth. The FDA is now in the process of trying to remove the drug's indication, though the drug maker, Roche, has appealed the decision.
AP Medical Writer Marilyn Marchione contributed reporting from Milwaukee.