Safety, Tolerability, and Preliminary Efficacy of the Anti-Fibrotic Small Molecule PRI-724, a CBP/β-Catenin Inhibitor, in Patients with Hepatitis C Virus-related Cirrhosis: A Single-Center, Open-Label, Dose Escalation Phase 1 Trial

BACKGROUND: There is currently no anti-fibrotic drug therapy available to treat hepatitis C virus (HCV) cirrhosis. The aim of this study was to assess the safety, tolerability, and anti-fibrotic effect of PRI-724, a small-molecule modulator of Wnt signaling, in patients with HCV cirrhosis. METHODS: In this single-center, open-label, phase 1 trial, we sequentially enrolled patients with HCV cirrhosis who were classified as Child-Pugh (CP) class A or B. PRI-724 was administered as a continuous intravenous infusion of 10, 40, or 160 mg/m(2)/day for six cycles of 1 week on and 1 week off. The primary endpoints were frequency and severity of adverse events. The secondary endpoint was efficacy of PRI-724 in treating cirrhosis based on CP score and liver biopsy. This study is registered with ClinicalTrials.gov (no. NCT02195440). FINDINGS: Between Sept 3, 2014 and May 2, 2016, 14 patients were enrolled: CP class A:B, 6:8; median age, 62 (range: 43 to 74) years; male:female, 10:4. Twelve of the 14 patients completed six cycles of treatment; one was withdrawn from the study due to possible study drug-related liver injury (grade 3) in the 160 mg/m(2)/day dose cohort and one withdrew for personal reasons. Serious adverse events occurred in three patients [21% (3/14)], one of which was possibly related to PRI-724. The most common adverse events were nausea [29% (4/14)] and fatigue [21% (3/14)]. After PRI-724 administration, the CP scores worsened by 1 point in two patients in the 10 mg/m(2)/day cohort, improved in three patients at 1, 1, and 2 points in the 40 mg/m(2)/day cohort, and improved in one patient by 3 points in the 160 mg/m(2)/day cohort. The histology activity index scores of the liver tissue improved in two patients and exacerbated in two patients in the 10 mg/m(2)/day cohort, and improved in one patient in the 40 mg/m(2)/day cohort. INTERPRETATION: This study showed that administration of 10 or 40 mg/m(2)/day intravenous PRI-724 over 12 weeks was well-tolerated by patients with HCV cirrhosis; however, liver injury as a possible related serious adverse event was observed in the 160 mg/m(2)/day cohort. FUNDING SOURCE: AMED.