The US Food and Drug Administration (FDA) has granted Vertex Pharmaceuticals’ new drug application and its request for a six-month priority review of Kalydeco (ivacaftor), used to treat cystic fibrosis.

Kalydeco, as a cystic fibrosis transmembrane conductance regulator potentiator, helps to hydrate and clear mucus from the airways.

The approval is backed by results from two Phase III studies, STRIVE and ENVISION, in which cystic fibrosis patients treated with Kalydeco experienced rapid and sustained improvements across a variety of disease measures, including lung function.

The STRIVE study, which involved patients in patients aged 12 and older with at least one copy of the G551D mutation, reported a mean absolute improvement in lung function of 10.6% points.

A relative mean improvement in lung function of 16.8% from baseline through to week 24 was also observed among those treated with Kalydeco compared with the placebo.

The second pivotal Phase III study, ENVISION, evaluated the efficacy of Kalydeco in children with cystic fibrosis aged between six and 11 years, and had at least one copy of the G551D mutation.

Vertex global research and development chief scientific officer and executive vice-president Peter Mueller said that, if Kalydeco is approved by the FDA, it will be the first treatment to target the underlying cause of cystic fibrosis.

The company said that its marketing authorisation application for Kalydeco has been validated by the European Medicines Agency (EMA).

"The commitments by the FDA and the EMA to expedite their reviews of our applications underscore the significant potential of Kalydeco to help people living with cystic fibrosis," Mueller said.

Caption: Vertex receives FDA new drug application approval for Kalydeco.