Ivacaftor Safe, Efficacious for Cystic Fibrosis

Improves pulmonary exacerbation, respiratory symptoms, weight, sweat chloride levels

WEDNESDAY, Nov. 2 (HealthDay News) -- Use of ivacaftor is associated with improved lung function in cystic fibrosis, according to a study published in the Nov. 3 issue of the New England Journal of Medicine.

Bonnie W. Ramsey, M.D., from Seattle Children's Hospital, and colleagues evaluated ivacaftor in the treatment of cystic fibrosis. Patients aged 12 years or older with at least one G551D-CFTR mutation were randomized to receive 150 mg ivacaftor every 12 hours (84 individuals) or placebo (83 individuals) for 48 weeks. The estimated mean change in the percent of predicted forced expiratory volume in one second (FEV1) from baseline through week 24 was the primary end point.

The investigators found that the change in the percent of predicted FEV1 in the ivacaftor group was significantly greater, by 10.6 percent, than in the placebo group. By two weeks, effects on pulmonary function were evident and the significant treatment effect was seen through week 48. Compared to individuals in the placebo group, those in the ivacaftor group were 55 percent less likely to develop a pulmonary exacerbation; scored 8.6 points higher on the respiratory-symptoms domain of the Cystic Fibrosis Questionnaire-revised instrument; gained an average of 2.7 kg weight; and had a change of −48.1 mmol per liter in concentration of sweat chloride, through week 48. Adverse event incidence was similar in the two groups, with a lower proportion of serious adverse events with ivacaftor.

"Ivacaftor was associated with improvements in lung function at two weeks that were sustained through 48 weeks," the authors write.

The study was partly funded by Vertex Pharmaceuticals, manufacturers of ivacaftor; several authors disclosed financial relationships with pharmaceutical companies, including Vertex.

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