The participants in this study will have confirmed PBC with inadequate response or intolerance to Ursodeoxycholic acid (UDCA), which is a medication used in the management and treatment of cholestatic liver disease.

Primary biliary cholangitis is a slowly progressive disease characterised by damage of the bile ducts in the liver, leading to a build-up of bile acids which causes further damage. The liver damage in PBC may lead to scarring (cirrhosis). PBC may also be associated with multiple symptoms.

Many patients with PBC may require a liver transplant or may die if the disease progresses and a liver transplant is not done. This study will compare a daily dose of elafibranor (the study drug) to a daily dose of placebo (a dummy treatment).

The main aim of this study is to determine if elafibranor is better than placebo in reducing ALP levels to a normal value. High ALP levels in the blood can indicate liver disease.

There will be three periods in this study: A screening period (up to 8 weeks) to assess whether the participant can take part; a treatment period (up to 52 weeks) where eligible participants will be grouped as per their blood ALP levels and randomly assigned to either receive elafibranor or placebo, and a follow-up period (4 weeks) where participants' health will be monitored.

Participants will be twice as likely to receive elafibranor than placebo (2:1 ratio).

Participants will undergo blood sampling, urine collections, physical examinations, clinical evaluations, electrocardiograms (ECG: recording of the electrical activity of heart), ultrasound examinations (a noninvasive test that passes a probe over skin to look at the bladder, urinary tract, and liver), and Fibroscan® examinations (a noninvasive test that passes a probe on skin to measure stiffness of the liver).

They will also be asked to fill in questionnaires. Each participant will be in this study for up to 64 weeks (15 months).