Vertex Pharma will be booking extra sales this year after European regulators expanded the use of its Cystic Fibrosis drug Kalydeco (ivacaftor).

Around 250 extra patients with CF stand to benefit from the drug after the European Medicines Agency gave the nod for its use when one of eight non-G551D gating mutations is present, widening the 2012 approval targeting those with G551D mutation.

Clearance is based on Phase III data from a study with 39 CF patients with a non-G551D gating mutation, which showed statistically-significant improvements in lung function (FEV1) and other measures of the disease, including sweat chloride and body mass index, the firm said.

CF is caused by a defective or missing CFTR protein and Kalydeco helps this protein function more normally, thus becoming the first medicines to address the underlying cause of the condition.