Patients with CF aged 6-11 years with a G551D-CFTR mutation on at least one allele.
Interventions
Patients were randomly assigned to receive ivacaftor administered orally at 150 mg (n=26) or placebo (n=26) every 12 hours for 48 weeks in addition to existing prescribed cystic fibrosis therapies.
Outcome measures
Forced expiratory volume in 1 second (FEV1); concentration of sweat chloride; incidence of adverse events
Main results
Despite near normal mean baseline values in forced expiratory volume in 1 second (FEV1), patients receiving ivacaftor had a significant increase in percent predicted FEV1 from baseline through Week 24 versus placebo group (treatment effect: 12.5 percentage points; P < 0.001). Effects on pulmonary function were evident by 2 weeks, and a significant treatment effect was maintained through Week 48. Patients treated with ivacaftor gained, on average, 2.8 kg more than those receiving placebo at Week 48 (P < 0.001). The change from baseline through Week 48 in the concentration of sweat chloride, a measure of CFTR activity, with ivacaftor was -53.5 mmol/liter (P < 0.001) versus placebo. The incidence of adverse events was similar in the two groups.
Authors' conclusions
In patients who are younger and healthier than those in previously studied populations, ivacaftor demonstrated a meaningful improvement in pulmonary function, weight, and CFTR activity compared with placebo.