PSC is a chronic disease which causes scarring of the bile ducts. When the bile ducts are damaged, the ducts become hard and narrow and this can block the flow of bile which can cause damage to the liver over time.
A clinical research study (also known as a clinical trial) is designed to help medical research learn more about disease and improve health care for people in the future, such as evaluating the safety and efficacy of an investigational drug for a disease or condition. The results of clinical studies help regulatory agencies like the U.S. Food and Drug Administration (FDA) to decide if an investigational drug works and is safe. Clinical trials offer a chance to help researchers find better treatments for others in the future.
This is a Phase 3 Study. Clinical trials are divided into 4 different phases:

Phase 1
Testing in a small number of healthy volunteers to learn about safety and identify side effects.

Phase 2
Testing in a small number of patients to evaluate effectiveness and to further study its safety.

Phase 3
Testing on a larger number of patients to gather more information about safety and effectiveness, study different populations and different dosages.

Phase 4
After a drug is approved by the regulatory body, researchers track its safety in the general population, seeking more information about the drug and its use.
Every clinical study is reviewed by an independent review board or ethics committee (IRB or EC), who helps ensure that the study is conducted safely and that the rights and safety of study participants are protected. Clinical trials are conducted by medical professionals who monitor the health of participants during the study.
This study is testing an investigational drug called cilofexor in adults with primary sclerosing cholangitis (PSC) to see if it can potentially slow the progress of liver scarring (fibrosis) caused by PSC. PSC is a chronic disease which causes scarring of the bile ducts. When the bile ducts are damaged, the ducts become hard and narrow and this can block the flow of bile which can cause damage to the liver over time. Around 400 people will participate in the study at about 200 study clinics around the world. The PRIMIS study will help evaluate the safety and effectiveness of cilofexor in a broader population of patients with PSC.

Participation in the study will last about 2 years and will require approximately 14 visits to the research clinic and multiple regularly scheduled phone calls.
The study is divided into several phases:
- Screening Period (up to 2 months): Tests will be performed to determine if you can enroll in the study and adjustments may be made to current medications. You may need to have a liver biopsy performed if you have not had one within the last 6 months.
- Study Treatment Period (about 22 months): You will be randomly assigned (like the flip of a coin) to study treatment with either the investigational drug (cilofexor) or placebo (an inactive substance). You have a 1 in 3 chance of receiving placebo. You will return to the study clinic every 1-3 months for health checks and study procedures. You will also have regularly scheduled calls with the study clinic to check on your health.
- Follow-Up Period: You will have one last visit about 4 weeks after the Study Treatment Period ends to check on your health and any potential side effects.
Take a quick survey & learn if you qualify now.
You may qualify to participate if you:
- Are 18 to 70 years of age
- Have been diagnosed with large duct PSC (a specific type of PSC)
- Do not have current or prior history of cirrhosis, liver transplant, bile duct cancer, cancer within the last 5 years, or unstable cardiovascular disease
- Do not have currently active inflammatory bowel disease (IBD) that is considered moderate to severe; examples of IBD include ulcerative colitis and Crohn’s disease
Other criteria will be reviewed to determine if you qualify for this study.
Please answer the questions below to help us determine if you may qualify for the PRIMIS clinical research study for primary sclerosing cholangitis (PSC). You must be between 18-70 years of age to complete this survey. If your responses indicate that you may qualify, you will be provided contact information of a study site within your chosen radius. Prequalification on this website does not guarantee your eligibility to participate in the study. Additional qualification criteria exist. Study site staff will answer any questions you may have and will discuss the next steps to determine whether you may qualify for this study.
What will happen to my information? The information you provide will not be stored. By answering this form, you are agreeing to provide permission to the host of this website to use your information for the purposes of determining whether you may qualify for the PRIMIS study for primary sclerosing cholangitis. For more information, please see our privacy policy
Thank you for your interest.
Based on your answers, you do not currently qualify to participate in the PRIMIS study for primary sclerosing cholangitis.
Thank you for taking the time to complete the study questionnaire. Based on your responses, it looks like you prequalify to be provided additional information about the study. To find out if there is a study center near you, please enter your Zip/Postal code and maximum travel distance below.