Hepatobiliary Disease USMLE Step 1 Practice Question

A 45-year-old woman presents to clinic with a 10-year history of primary biliary cholangitis (PBC) diagnosed by positive anti-mitochondrial antibody and liver biopsy. She reports progressive fatigue, pruritus, and jaundice over the past 6 months. She has been compliant with ursodeoxycholic acid (UDCA) 13-15 mg/kg/day for 8 years. Current laboratory values show: alkaline phosphatase 280 U/L (normal <120), gamma-glutamyl transferase 320 U/L (normal <55), total bilirubin 2.8 mg/dL (normal <1.2), ALT 35 U/L (normal <40), and AST 42 U/L (normal <40). Abdominal ultrasound shows no evidence of portal hypertension or cirrhosis. Which of the following is the most appropriate next pharmacologic intervention to slow disease progression?