The FDA has approved Kalydeco (ivacaftor), manufactured by Vertex Pharmaceuticals, for the treatment of a rare form of cystic fibrosis in patients ages six and older who have the specific G551D mutation in the Cystic Fibrosis Transmembrane Regulator (CFTR) gene.

Cystic fibrosis is a serious genetic disorder affecting the lungs and other organs that ultimately leads to an early death. Of the 30,000 people in the U.S. with the common form, 4% are believed to have the G551D mutation.

The FDA reviewed and approved Kalydeco in approximately three months under the agency’s priority review program that is designed to expedite drugs of possible significance. Kalydeco was approved ahead of the drug’s April 18, 2012, prescription user fee goal date and is designated as an orphan drug, which identifies the disease as affecting fewer than 200,000 people in the U.S.

“Kalydeco is an excellent example of the promise of personalized medicine—targeted drugs that treat patients with a specific genetic makeup,” said FDA commissioner Margaret A. Hamburg, M.D.

In patients with the G551D mutation, Kalydeco, a pill taken two times a day with fat-containing food, helps the protein made by the CFTR gene function better and as a result, improves lung function and other aspects of CF such as increasing weight gain.

Two 48-week, placebo-controlled clinical studies involving 213 patients, one in patients ages 12 and older and another in patients ages six to 11, were used to evaluate the safety and efficacy of Kalydeco in cystic fibrosis patients with the G551D mutation. In both studies, treatment with Kalydeco resulted in significant and sustained improvement in lung function.