Human Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of ASC42, a Novel Farnesoid X Receptor Agonist.

Background: ASC42 is a non-steroidal farnesoid X receptor agonist currently in clinical development for chronic liver diseases, such as nonalcoholic fatty liver disease/nonalcoholic steatohepatitis (NAFLD/NASH) and primary biliary cirrhosis (PBC).

Objective: The objective of this study was to assess the safety, pharmacokinetics (PK), and pharmacodynamics (PD) of ASC42 in healthy subjects.

Methods: We conducted the first-in-human study of ASC42 following single and multiple ascending doses (SAD/MAD) and food effect in healthy subjects. The SAD study included five cohorts receiving 5-200 mg ASC42 or placebo and one cohort that was given 15 mg ASC42 with a high-fat meal. The MAD study included three cohorts receiving 5-50 mg ASC42 or placebo once-daily (QD) for 14 days.

Results: A total of 65 healthy subjects were enrolled and one subject in the MAD study (cohort 8, ASC42 50 mg) withdrew from the study due to an unrelated serious adverse event (SAE) of atrial fibrillation. Pruritus was observed at the highest doses (200 mg cohort in SAD and 50 mg cohort in MAD). Most AEs were mild or moderate. No life-threatening or fatal AEs occurred. ASC42 showed a proportional increase in exposure and elimination half-life following both single and multiple dosing. There was a 21% and 37% decrease in area under the curve (AUC) and maximum plasma concentration (C_max) when ASC42 was coadministered with food. The steady state was reached on day 4 with a mild accumulation (1.02-1.74-fold). ASC42 showed dose-dependent increases in fibroblast growth factor 19 and decreases in 7α-hydroxy-4-cholesten-3-one. Cholesterol remained within normal limits during study.

Conclusion: ASC42 was well tolerated with a pharmacokinetic profile suitable for QD dosing, and demonstrated dose-dependent targets engagement without altering plasma cholesterol in healthy subjects.

Trial registration number: NCT04679129.