Cystic Fibrosis Drug Ivacaftor (Kalydeco) Fails to Meet Primary Endpoint in Phase III Trial
Study focuses on patients with R117H mutation (December 19)
Mixed results have been reported from a phase III study of ivacaftor (Kalydeco, Vertex Pharmaceuticals) in 69 patients 6 years of age and older with cystic fibrosis (CF) who have the R117H mutation. In the study, the mean absolute treatment difference in the change from baseline in percent predicted forced expiratory volume in 1 second (FEV1) between treatment with ivacaftor and placebo was 2.1% (P = 0.20) and the mean relative treatment difference in percent predicted FEV1 was 5.0% (P = 0.06) through the 24-week treatment period among all patients (intent-to-treat analysis).
Thus, the study did not meet its primary endpoint of the absolute change from baseline in FEV1 throughout the treatment period for ivacaftor compared with placebo across all patients.
However, a prespecified subset analysis in patients 18 years of age and older (n = 50) showed statistically significant improvements in lung function and other key secondary endpoints. In these patients, the mean absolute treatment difference in percent predicted FEV1 between treatment with ivacaftor and placebo was 5.0% (P = 0.01) and the mean relative treatment difference in percent predicted FEV1 was 9.1% (P = 0.008) through the 24-week treatment period.
R117H is the most common residual function mutation. In North America, Europe, and Australia, approximately 1,100 people with CF aged 6 years and older have at least one copy of an R117H mutation. In the U.S., approximately 300 people have the R117H mutation and are 18 years of age or older.
Source: Vertex Pharmaceuticals; December 19, 2013.