Efficacy response in CF patients treated with ivacaftor: Post-hoc analysis

Michael W. Konstan, Barry J. Plant, J. Stuart Elborn, Sally Rodriguez, Anne Munck, Richard Ahrens, Charles Johnson

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)


Clinical studies in patients with cystic fibrosis and G551D-CFTR showed that the group treated with ivacaftor had improved clinical outcomes. To better understand the effect of ivacaftor therapy across the distribution of individual FEV1 responses, data from Phase 3 studies (STRIVE/ENVISION) were re-examined. In this post-hoc analysis of patients (n=209) who received 48 weeks of ivacaftor or placebo, patients were assigned to tertiles according to FEV1 response. These groups were then used to evaluate response (FEV1, sweat chloride, weight, CFQ-R, and pulmonary exacerbation). The number needed to treat (NNT) was calculated for specific thresholds for each outcome. Across all tertiles, numerical improvements in FEV1, sweat chloride, CFQ-R and the frequency of pulmonary exacerbations were observed in ivacaftor-treated patients: the treatment difference versus placebo was statistically significant for all outcomes in the upper tertile and for some outcomes in the lower and middle tertiles. The NNT for a≥5% improvement in %predicted FEV1 was 1.90, for a≥5% body weight increase was 5.74, and to prevent a pulmonary exacerbation was 3.85. This analysis suggests that the majority of patients with clinical characteristics similar to STRIVE/ENVISION patients have the potential to benefit from ivacaftor therapy.
Original languageEnglish
Pages (from-to)447-455
Number of pages9
JournalPediatric Pulmonology
Issue number5
Early online date09 Mar 2015
Publication statusPublished - May 2015


  • CFTR
  • Clinical response
  • Cystic fibrosis
  • Ivacaftor


Dive into the research topics of 'Efficacy response in CF patients treated with ivacaftor: Post-hoc analysis'. Together they form a unique fingerprint.

Cite this