Investigational Drug Targets Cystic Fibrosis Mutation and Regulator

Trial Objective

Investigational Drug Targets Cystic Fibrosis Mutation and RegulatorOur researchers are studying glycerol phenylbutyrate (GPBA), also known as RAVICTI®, to determine how safe it is and how well people tolerate it in the treatment of cystic fibrosis (CF).

Pancreatic enzymes are needed to release the active molecules of GPBA, which is an oil of phenylbutyrate, a drug used to treat urea-cycle disorders. This study will determine if GPBA (RAVICTI®) improves the function of a specific gene mutation (F508del) for a protein called the cystic fibrosis transmembrane conductance regulator (CFTR). The study also will measure how typical pancreatic enzyme replacement therapy (PERT) affects absorption of active phenylbutyrate.

RAVICTI® is the brand name of a GPBA drug approved by the Food and Drug Administration (FDA) for the treatment of urea-cycle disorders. RAVICTI® is not approved for treatment of cystic fibrosis, and its use in this study is investigational.


New enrollment for this trial is temporarily paused

Who Can Participate

 Adults with cystic fibrosis (CF) who have documentation of two copies of the F508del cystic fibrosis transmembrane conductance regulator (CFTR) mutation, a forced expiratory volume during the first second of air exhaled (FEV1) equal to or greater than 30 percent, and who take pancreatic enzyme replacement therapy (PERT) may be eligible to participate.

Age: 18+    Gender: Any Gender

Estimated Time Commitment

5 visits totalling up to 21 hours

Payment & Reimbursement  

Payment: Provided

Travel Reimbursement: Available

Trial Contact

For more information, contact:

Alix Wilson

Alexandra Wilson

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Trial Location

National Jewish Main Campus, Denver, CO

Trial Sponsors

Food and Drug Administration and Cystic Fibrosis Foundation Therapeutics, Inc., with research support from  Horizon Pharma

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Due to concerns around COVID-19 and our focus on helping to meet this momentous challenge, we have temporarily paused enrollment for all trials requiring an in-person visit. Please feel free to request additional information about any of the trials we have posted and we will get back to you when enrollment resumes. For more resources and information on COVID-19 please visit our special coronavirus website at