(Study: Vertex IIS) Does Ivacaftor Alter Wild Type CFTR-Open Probability In The Sweat Gland Secretory Coil?

Not Recruiting

Trial ID: NCT02310789


Clinical studies of lumacaftor + ivacaftor (combo therapy) produced better FEV1 (forced expiratory volume in 1 second) improvements than ivacaftor alone, without further improvement in sweat chloride results. To help understand why sweat chloride was unresponsive, the investigators will use a newly developed sweat secretion test that provides accurate, in vivo readout of CFTR (cystic fibrosis transmembrane conductance regulator) function in the sweat gland secretory coil. The investigators devised a protocol to determine if short courses of ivacaftor (3.5 days) will produce significant increases in WT (Wild-Type, i.e. normal) CFTR open probability by measuring CFTR-dependent sweating (C-sweat) in subjects with WT CFTR.

Official Title

(Study: Vertex IIS) A Study To Access the Effects of Ivacaftor on Wild Type CFTR-Open Probability (PO) In The Sweat Gland Secretory Coil

Stanford Investigator(s)


Inclusion Criteria:

   - Healthy adults without a Cystic Fibrosis (CF) mutation

   - Carriers with a known CF mutation

Exclusion Criteria:

   1. Documented liver disease

   2. Participants should not be taking:

      - medicines that are strong CYP3A (Cytochrome P450, family 3, subfamily A)
      inducers, such as:

         - the antibiotics rifampin and rifabutin;

         - seizure medications (phenobarbital, carbamazepine, or phenytoin); and

         - the herbal supplement St. John's Wort, substantially decreases exposure of
         ivacaftor and may diminish effectiveness.


drug: Ivacaftor

drug: β-Adrenergic cocktail

drug: Pilocarpine Nitrate 5%

device: Macroduct sweat stimulator

Not Recruiting

Contact Information

Stanford University
School of Medicine
300 Pasteur Drive
Stanford, CA 94305
Colleen Dunn, RRT, CCRC