A Study of Experimental PLN-74809 in Cholangitis and Suspected Liver Fibrosis

Open to people ages 18-75

• Established clinical diagnosis of large duct PSC based on an abnormal cholangiography as assessed by magnetic resonance cholangiopancreatography (MRCP), endoscopic retrograde cholangiopancreatography (ERCP), and/or percutaneous transhepatic cholangiopancreatography (PTC) in the context of cholestatic liver chemistry
• Suspected liver fibrosis, as defined by liver stiffness measurement (LSM), assessed by ultrasound-based transient elastography (TE, FibroScan®) OR Enhanced Liver Fibrosis (ELF) Score OR Historical liver biopsy showing fibrosis without cirrhosis (by any scoring system) OR Magnetic resonance elastography (MRE)
• Serum ALP concentration > 1 times the upper limit of normal (ULN)
• Participants receiving treatment for IBD are allowed, if on a stable dose from screening and expected to remain stable for the duration of the study
• Serum AST and ALT concentration ≤ 5 times the upper limit of normal
• If receiving treatment with UDCA, therapy is at a dose of < 25 mg/kg/day, has been stable for at least 3 months before screening.

• Other causes of liver disease, including secondary sclerosing cholangitis or viral, metabolic, or alcoholic liver disease, as assessed clinically
• Known or suspected overlapping clinical and histologic diagnosis of autoimmune hepatitis
• Small duct PSC (evidence of PSC on historical liver histology, with normal bile ducts on cholangiography)
• Presence of liver cirrhosis as assessed by liver histology, ultrasound-based liver stiffness measurement, ELF score, MRE, and/or signs and symptoms of hepatic decompensation (including but not limited to, jaundice, ascites, variceal hemorrhage, and/or hepatic encephalopathy.
• Serum ALP concentration > 10 times the upper limit of normal.