A randomized, placebo-controlled, phase II study of obeticholic acid for primary sclerosing cholangitis.

Background & Aims: Primary sclerosing cholangitis (PSC) is a rare, cholestatic liver disease with no currently approved therapies. Obeticholic acid (OCA) is a potent farnesoid X receptor (FXR) agonist approved for the treatment of primary biliary cholangitis. We investigated the efficacy and safety of OCA in patients with PSC.

Methods: AESOP was a phase II, randomized, double-blind, placebo-controlled, dose-finding study. Eligible patients were 18 to 75 years of age with a diagnosis of PSC and serum alkaline phosphatase (ALP) ≥2× the upper limit of normal (ULN) and total bilirubin <2.5× ULN. Patients were randomized 1:1:1 to receive placebo, OCA 1.5-3.0 mg, or OCA 5-10 mg once daily for a 24-week, double-blind phase followed by a 2-year, long-term safety extension (LTSE). Primary endpoints were change in ALP from baseline to week 24, and safety.

Results: The intent-to-treat population comprised 76 patients randomized to placebo (n = 25), OCA 1.5-3.0 mg (n = 25), and OCA 5-10 mg (n = 26). At week 24, serum ALP was significantly reduced with OCA 5-10 mg vs. placebo (least-square [LS] mean difference = -83.4 [SE = 40.3] U/L; 95% CI -164.28 to -2.57; p = 0.043). Serum ALP was not significantly reduced with OCA 1.5-3.0 mg vs. placebo at week 24 (LS mean [SE] difference = -78.29 [41.81] U/L; 95% CI -162.08 to 5.50; p = 0.067). Total bilirubin remained comparable to baseline in all groups. The most common treatment-emergent adverse event was dose-related pruritus (placebo 46%; OCA 1.5-3.0 mg 60%; OCA 5-10 mg 67%). Reductions in ALP were maintained during the LTSE, and no new safety signals emerged.

Conclusions: Treatment with OCA 5-10 mg reduced serum ALP in patients with PSC. Mild to moderate dose-related pruritus was the most common adverse event.

Registration: ClinicalTrials.gov: NCT02177136; EudraCT: 2014-002205-38.

Lay Summary: Primary sclerosing cholangitis (PSC) is a long-term disease that damages the bile ducts in the liver over time. In the AESOP clinical study in patients with PSC, obeticholic acid reduced serum alkaline phosphatase (a potential marker of disease severity) during an initial 24-week treatment period. The result was sustained during the 2-year, long-term extension of the study. The most common side effect of obeticholic acid in the study was itchy skin, which is consistent with earlier clinical studies.