A Study of HTD1801 in Adolescents With Primary Sclerosing Cholangitis (PSC)

Inclusion Criteria: * Weight ≥ 35 kg * Previous cholangiographic evidence of PSC by magnetic resonance cholangiopancreatography (MRCP) or direct cholangiography or liver biopsy findings * Serum GGT ≥ 2 × upper limit of normal (ULN) * On a stable UDCA treatment regimen for ≥ 8 weeks Exclusion Criteria: * Secondary sclerosing cholangitis * Percutaneous or endoscopically-placed biliary drain or stent * History of cholangiocarcinoma or clinical suspicion of new dominant stricture within 1 year * Ascending cholangitis requiring intravenous antibiotic therapy within 60 days prior to Screening * Concomitant overlap syndrome with primary biliary cholangitis (PBC) * Significant hepatic decompensation * Alternative causes of chronic liver disease * Hospitalization for colitis within 30 days prior to Screening * Serum creatinine \> 1.2 x ULN * Hemoglobin \< 10 g/dL * Glucose-6-phosphate dehydrogenase (G6PD) deficiency