Vertex Pharmaceuticals (Europe) Limited announced that the European Commission has granted approval of the label extension for ORKAMBI® (lumacaftor/ivacaftor) for the treatment of children with cystic fibrosis (CF) aged 2 to 5 years old who have two copies of the F508del mutation, the most common form of the disease. The label update is based on data from a Phase 3 open-label safety study in 60 patients that showed treatment with lumacaftor/ivacaftor was generally well tolerated for 24 weeks, with a safety profile in these pediatric patients generally consistent with that in patients aged 6 years and older. Lumacaftor/ivacaftor is already approved in the EU for the treatment of CF in patients aged 6 and older who have two copies of the F508del mutation. This European Commission approval is based on a Phase 3 open-label safety study in 60 patients that showed treatment with lumacaftor/ivacaftor was generally well tolerated for 24 weeks, with a safety profile similar to that in patients aged 6 years and older. Improvements in sweat chloride, a secondary endpoint, were observed at week 24 (mean decrease in sweat chloride from baseline of 31.7 mmol/L; 95% CI: -35.7, -27.6, n=49). Researchers also saw changes in key growth parameters, which were also secondary endpoints in the study. The most common adverse event (=30% overall) was cough (63%); most adverse events were mild or moderate in severity. Four patients experienced serious adverse events (2 infective pulmonary exacerbations of cystic fibrosis, 1 gastroenteritis viral, 1 constipation) and three patients discontinued treatment due to elevated transaminases without concurrent elevations in total bilirubin. These findings were presented at the 41stEuropean Cystic Fibrosis Society Conference in June 2018. Lumacaftor/ivacaftor is a combination of lumacaftor, which is designed to increase the amount of mature protein at the cell surface by targeting the processing and trafficking defect of the F508del-CFTR protein, and ivacaftor, which is designed to enhance the function of the CFTR protein once it reaches the cell surface.