FDA Approves Drug for Rare Form of Cystic Fibrosis

The FDA announced today that it has approved Kalydeco (ivacaftor) to treat cystic fibrosis caused by a rare genetic mutation. The drug was approved in just three months under the agency’s priority review program and was developed by its manufacturer, Vertex Pharmaceuticals Inc., with assistance from the Cystic Fibrosis Foundation.

Ivacaftor is specifically designed to treat patients with the G551D mutation in the Cystic Fibrosis Transmembrane Regulator (CFTR) gene. Of the 30,000 people in the US with cystic fibrosis, about 4%, or 1,200, have the G551D mutation. The drug’s approval was based on two Phase 3 trials including a total of 213 patients with the mutation. Both studies found that, compared with a placebo, ivacaftor led to significant and sustained improvement in lung function, increased weight gain and quality of life, and fewer pulmonary exacerbations.

“Kalydeco is the first available treatment that targets the defective CFTR protein, which is the underlying cause of cystic fibrosis,” said Janet Woodcock, MD, director of the FDA’s Center for Drug Evaluation and Research, in a press release. “This is a breakthrough therapy for the cystic fibrosis community because current therapies only treat the symptoms of this genetic disease.”

The Cystic Fibrosis Foundation provided $75 million in initial funding to Vertex Pharmaceuticals as part of its venture philanthropy drug development model, which aims to encourage pharmaceutical companies to develop drugs for rare diseases. The foundation’s future goals include developing therapies for those with the Delta F508 mutation, which causes about 90% of cystic fibrosis cases.