Trial reportPloS one2013
Optimizing nasal potential difference analysis for CFTR modulator development: assessment of ivacaftor in CF subjects with the G551D-CFTR mutation.
Trial report in PloS one, 2013. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 32 papers, 1 of them a synthesis that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
32 citing papers in PubMed, 1 synthesis or guideline pooled it.
- Potentiators (specific therapies for class III and IV mutations) for cystic fibrosis.The Cochrane database of systematic reviews · 2019Pooled it
- Ivacaftor for Chronic Obstructive Pulmonary Disease: Results from a Phase 2, Randomized Controlled Trial.American journal of respiratory and critical care medicine · 2025Trial
- Moderate intensity exercise mediates comparable increases in exhaled chloride as albuterol in individuals with cystic fibrosis.Respiratory medicine · 2015Trial
- Molecular Prosthetics and CFTR Modulators Additively Increase Secretory HCOACS chemical biology · 2025Article
- Toward in vivo bronchoscopic functional CFTR assessment using a short circuit current measurement probe.American journal of physiology. Lung cellular and molecular physiology · 2025Article
- A case study of the informative value of risk of bias and reporting quality assessments for systematic reviews.Systematic reviews · 2024Article
- A Systematic Review of the Effect of Cystic Fibrosis Treatments on the Nasal Potential Difference Test in Animals and Humans.Diagnostics (Basel, Switzerland) · 2023Review
- Effect of lumacaftor-ivacaftor on mucociliary clearance and clinical outcomes in cystic fibrosis: Results from the PROSPECT MCC sub-study.Journal of cystic fibrosis : official journal of the European Cystic Fibrosis Society · 2022Article
- Patient personalized translational tools in cystic fibrosis to transform data from bench to bed-side and back.American journal of physiology. Gastrointestinal and liver physiology · 2021Article
- Amphotericin B induces epithelial voltage responses in people with cystic fibrosis.Journal of cystic fibrosis : official journal of the European Cystic Fibrosis Society · 2021Article
- Ivacaftor Reverses Airway Mucus Abnormalities in a Rat Model Harboring a Humanized G551D-CFTR.American journal of respiratory and critical care medicine · 2020Article
- Ocular Surface Potential Difference Measured in Human Subjects to Study Ocular Surface Ion Transport.Translational vision science & technology · 2020Article
- Antibiotic eluting sinus stents.Laryngoscope investigative otolaryngology · 2020Review
- Antisense oligonucleotide eluforsen improves CFTR function in F508del cystic fibrosis.Journal of cystic fibrosis : official journal of the European Cystic Fibrosis Society · 2019Article
- In-vitro evaluation of a ciprofloxacin- and ivacaftor-coated sinus stent against Pseudomonas aeruginosa biofilms.International forum of allergy & rhinology · 2019Article
- Ivacaftor, a Cystic Fibrosis Transmembrane Conductance Regulator Potentiator, Enhances Ciprofloxacin Activity Against Pseudomonas aeruginosa.American journal of rhinology & allergy · 2019Article
- CFTR modulator theratyping: Current status, gaps and future directions.Journal of cystic fibrosis : official journal of the European Cystic Fibrosis Society · 2019Review
- Article
- The epithelial sodium channel (ENaC) as a therapeutic target for cystic fibrosis.Current opinion in pharmacology · 2018Review
- Ion Channel Modulators in Cystic Fibrosis.Chest · 2018Review
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
13 authors.
Funding
Abstract
Nasal potential difference (NPD) is used as a biomarker of the cystic fibrosis transmembrane conductance regulator (CFTR) and epithelial sodium channel (ENaC) activity. We evaluated methods to detect changes in chloride and sodium transport by NPD based on a secondary analysis of a Phase II CFTR-modulator study. Thirty-nine subjects with CF who also had the G551D-CFTR mutation were randomized to receive ivacaftor (Kalydeco™; also known as VX-770) in four doses or placebo twice daily for at least 14 days. All data were analyzed by a single investigator who was blinded to treatment assignment. We compared three analysis methods to determine the best approach to quantify changes in chloride and sodium transport: (1) the average of both nostrils; (2) the most-polarized nostril at each visit; and (3) the most-polarized nostril at screening carried forward. Parameters of ion transport included the PD change with zero chloride plus isoproterenol (CFTR activity), the basal PD, Ringer's PD, and change in PD with amiloride (measurements of ENaC activity), and the delta NPD (measuring CFTR and ENaC activity). The average and most-polarized nostril at each visit were most sensitive to changes in chloride and sodium transport, whereas the most-polarized nostril at screening carried forward was less discriminatory. Based on our findings, NPD studies should assess both nostrils rather than a single nostril. We also found that changes in CFTR activity were more readily detected than changes in ENaC activity, and that rigorous standardization was associated with relatively good within-subject reproducibility in placebo-treated subjects (± 2.8 mV). Therefore, we have confirmed an assay of reasonable reproducibility for detecting chloride-transport improvements in response to CFTR modulation.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.