A randomized, double-blind, placebo-controlled study to evaluate the safety, pharmacokinetics and ammonia-lowering effect of Rifaquizinone, an intestinally restricted investigational drug.

Abstract

Background: Rifaquizinone (RQZ, TNP-2092) is a novel drug for treating hepatic encephalopathy (HE). This study assessed the safety, pharmacokinetics (PK), and efficacy of RQZ capsules in healthy participants and cirrhosis patients with hyperammonemia.

Research design and methods: We conducted three double-blind, randomized, placebo-controlled trials. Trials 1 and 2 enrolled healthy participants, while Trial 3 involved 36 cirrhosis patients with hyperammonemia.

Results: In healthy participants and liver cirrhosis patients with hyperammonemia, RQZ was safe and well tolerated. Adverse events were generally mild or moderate. Both food and liver cirrhosis disease status increased the exposure of RQZ, which was around 1% of that of the corresponding doses after intravenous administration. The effect in lowering blood ammonia was dose-dependent. The changes from baseline in blood ammonia levels at day 15 were -14.1 and 0.5 μmol/L in 600 mg and placebo cohort. The percentage of achieving normal blood ammonia during treatment were 31.9% and 7.4% in 600 mg and placebo cohort.

Conclusions: Although this study enrolled a relatively small cohort of cirrhotic patients with hyperammonemia, RQZ demonstrated an excellent safety profile as an intestinally restricted agent and showed promising potential for lowering blood ammonia and treating hepatic encephalopathy.