Effect of a High-Fat Meal on Single-Dose Rencofilstat (CRV431) Oral Bioavailability in Healthy Human Subjects.

Rencofilstat (RCF) is a novel cyclophilin inhibitor under development for the treatment of nonalcoholic steatohepatitis and hepatocellular carcinoma. This phase 1, randomized, open-label study in healthy participants assessed the relative bioavailability of a single dose of RCF 225-mg soft gelatin capsules in both fasted and high-fat conditions. Forty-four participants were enrolled to either the fasted (n = 24) or the high-fat fed (n = 20) arm. Noncompartmental pharmacokinetics were evaluated following a single 225-mg oral dose. Administration of RCF with a high-fat meal led to increases in maximum concentration, area under the concentration-time curve (AUC) from time 0 to 24 hours, and AUC from time 0 to infinity fed-to-fasted geometric mean ratios of 102.2%, 114.5%, and 132.9%, respectively. All AUC geometric mean ratios were outside of the 80% to 125% range, suggesting that a high-fat meal can increase the extent of RCF exposure. Time to maximum concentration increased from 1.5 to 1.8 hours in the fasted and high-fat groups, respectively, suggesting slightly delayed absorption. High fat intake may delay gastric emptying while increasing the absorption and bioavailability of RCF. No treatment-emergent adverse events were observed in the fasted group, and 1 treatment-emergent adverse event occurred in the high-fat meal group. The differences in observed whole-blood concentrations are unlikely to have clinically relevant effects given the wide therapeutic index of RCF demonstrated in previous phase 1 studies.

Rencofilstat, a cyclophilin inhibitor: A phase 2a, multicenter, single-blind, placebo-controlled study in F2/F3 NASH.

Rencofilstat (RCF) demonstrated antifibrotic effects in preclinical models and was safe and well tolerated in Phase 1 studies. The aim of this Phase 2a study was safety, tolerability, pharmacokinetics, and exploration of efficacy biomarkers in subjects with nonalcoholic steatohepatitis (NASH). This Phase 2a, multicenter, single-blind, placebo-controlled study randomized 49 presumed F2/F3 subjects to RCF 75 mg once daily (QD), RCF 225 mg QD, or placebo for 28 days. Primary safety and tolerability endpoints were explored using descriptive statistics with post hoc analyses comparing active to placebo groups. Pharmacokinetics were evaluated using population pharmacokinetics methods. Efficacy was explored using biomarkers, transcriptomics, and lipidomics. RCF was safe and well tolerated, with no safety signals identified. The most frequently reported treatment-emergent adverse events were constipation, diarrhea, back pain, dizziness, and headache. No clinically significant changes in laboratory parameters were observed, and RCF pharmacokinetics were unchanged in subjects with NASH. Alanine transaminase (ALT) reduction was greater in active subjects than in placebo groups. Nonparametric analysis suggested that ALT reductions were statistically different in the 225-mg cohort compared with matching placebo: -16.3 ± 25.5% versus -0.7 ± 13.4%, respectively. ProC3 and C6M reduction was statistically significant in groups having baseline ProC3 > 15.0 ng/ml. RCF was safe and well tolerated after 28 days in subjects with presumed F2/F3 NASH. Presence of NASH did not alter its pharmacokinetics. Reductions in ALT, ProC3, and C6M suggest direct antifibrotic effects with longer treatment duration. Reductions in key collagen genes support a mechanism of action via suppression and/or regression of collagen deposition. Conclusion: These results support advancement of rencofilstat into a larger and longer Phase 2b study.

Cyclophilin inhibition as a potential treatment for nonalcoholic steatohepatitis (NASH).

Introduction: Cyclophilins are a family of diverse regulatory enzymes that have been studied for over 30 years; they participate in many pathophysiological processes. Genetic deletion or pharmacologic inhibition of cyclophilins has shown therapeutic effects in a wide spectrum of disease models, including liver disorders, and hence may be beneficial in treating nonalcoholic steatohepatitis (NASH).Areas Covered: This articles briefly describes cyclophilin isomerases and the main classes of cyclophilin antagonists; it then summarizes data showing cyclophilin participation in the major pathophysiological activities that occur in NASH.Expert Opinion: Optimization of therapeutic outcomes in the treatment of NASH may be best realized by targeting multiple pathologic pathways, especially when treating advanced stages of the disease. A preferred approach for achieving this goal is to use compounds such as cyclophilin inhibitors that simultaneously target multiple disease processes. The pleiotropic benefits of this drug class derive from the extraordinary functionality of prolyl isomerization as a regulatory mechanism and its evolutionary diversification into many biochemical pathways. Nonimmunosuppressive analogs of cyclosporine A are the most thoroughly characterized cyclophilin inhibitors and show significant potential to attenuate several of the major pathophysiological events in NASH - mitochondrial dysfunction, cellular injury and death, inflammation, and in particular, fibrosis.

A Pan-Cyclophilin Inhibitor, CRV431, Decreases Fibrosis and Tumor Development in Chronic Liver Disease Models.

Previous studies show that cyclophilins contribute to many pathologic processes, and cyclophilin inhibitors demonstrate therapeutic activities in many experimental models. However, no drug with cyclophilin inhibition as the primary mode of action has advanced completely through clinical development to market. In this study, we present findings on the cyclophilin inhibitor, CRV431, that highlight its potential as a drug candidate for chronic liver diseases. CRV431 was found to potently inhibit all cyclophilin isoforms tested-A, B, D, and G. Inhibitory constant or IC50 values ranged from 1 to 7 nM, which was up to 13 times more potent than the parent compound, cyclosporine A (CsA), from which CRV431 was derived. Other CRV431 advantages over CsA as a nontransplant drug candidate were significantly diminished immunosuppressive activity, less drug transporter inhibition, and reduced cytotoxicity potential. Oral dosing to mice and rats led to good blood exposures and a 5- to 15-fold accumulation of CRV431 in liver compared with blood concentrations across a wide range of CRV431 dosing levels. Most importantly, CRV431 decreased liver fibrosis in a 6-week carbon tetrachloride model and in a mouse model of nonalcoholic steatohepatitis (NASH). Additionally, CRV431 administration during a late, oncogenic stage of the NASH disease model resulted in a 50% reduction in the number and size of liver tumors. These findings are consistent with CRV431 targeting fibrosis and cancer through multiple, cyclophilin-mediated mechanisms and support the development of CRV431 as a safe and effective drug candidate for liver diseases. SIGNIFICANCE STATEMENT: Cyclophilin inhibitors have demonstrated therapeutic activities in many disease models, but no drug candidates have yet advanced completely through development to market. In this study, CRV431 is shown to potently inhibit multiple cyclophilin isoforms, possess several optimized pharmacological properties, and decrease liver fibrosis and tumors in mouse models of chronic liver disease, which highlights its potential to be the first approved drug primarily targeting cyclophilin isomerases.

Development, Characterization, and Pharmacokinetic Evaluation of a CRV431 Loaded Self-Microemulsifying Drug Delivery System.

PURPOSE: The objective of this study was to develop a self-microemulsifying drug delivery system (SMEDDS) formulation for the oral delivery of CRV431, a non-immunosuppressive analogue of cyclosporine A. Relative to cyclosporine A, CRV431 is poorly soluble in lipid solvents and thusly presents a challenge for the development of a formulation of sufficient oral bioavailability for clinical use. METHODS: The solubility of CRV431, a cyclosporine derivative, was determined in a range of commonly used surfactants, oils and co-solvents. A pseudo-ternary phase diagram was constructed from the most soluble excipients and prototype formulations, SERIES 1 and SERIES 2 were developed. The pharmacokinetics, following single oral doses of 1 and 3 mg/kg of CRV431 SMEDDS, was studied in healthy human volunteers using liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS). RESULTS: The maximum drug load for the SERIES 1 formulations was less than 40 mg/ml. Manipulation of the excipient ratios allowed for the development of SERIES 2 formulations, which had higher drug loading capacity and stability for CRV431 compared to SERIES 1. Further improvements allowed for the development of an optimized SMEDDS formulation containing up to 90 mg/ml CRV431 and which generated a microemulsion mean particle size of 25 nm when dispersed into aqueous media. The pharmacokinetics of the optimized CRV431 SMEDDS displayed excellent total body exposure and dose-proportional effects in humans, and high drug levels in the liver of rats. CONCLUSIONS: The developed SMEDDS formulation should allow for effective clinical development of CRV431, targeted to the treatment of liver diseases including hepatitis B (HBV), fibrosis, and hepatocellular carcinoma.

In Vitro Phase I Metabolism of CRV431, a Novel Oral Drug Candidate for Chronic Hepatitis B.

The cytochrome P450-mediated Phase I in vitro metabolism of CRV431 was studied using selective chemical inhibition and recombinant human enzymes. Additionally, the metabolic profile of CRV431 in human, rat, and monkey liver microsomes was investigated. Liver microsomes were incubated for 0-80 min with CRV431, and the metabolite profile was assessed by electrospray ionization liquid chromatography mass spectrometry (ESI-LCMS). CRV431 was extensively metabolized through oxidation to produce various hydroxylated and demethylated species. Species identified included monohydroxylated CRV431 (two distinct products), dihydroxylated CRV431, demethylated CRV431 (two distinct products), demethylated and hydroxylated CRV431 (two distinct products), didemethylated and hydroxylated CRV431, and didemethylated and dihydroxylated CRV431. The magnitude of metabolism was greatest in monkey, followed by human, followed by rat. Importantly, all of the species identified in human microsomes were correspondingly identified in monkey and/or rat microsomes. Human liver microsome studies using selective chemical inhibition, as well as studies using recombinant human cytochrome P450 enzymes, revealed that the major enzymes involved are cytochromes P450 3A4 and 3A5. Enzymes 1A2, 2B6, 2C8, 2C9, 2C19, and 2D6 are not involved in the in vitro metabolism of CRV431. This information will be useful for the further development of CRV431 both preclinically and clinically.

The Novel Cyclophilin Inhibitor CPI-431-32 Concurrently Blocks HCV and HIV-1 Infections via a Similar Mechanism of Action.

HCV-related liver disease is the main cause of morbidity and mortality of HCV/HIV-1 co-infected patients. Despite the recent advent of anti-HCV direct acting antivirals (DAAs), the treatment of HCV/HIV-1 co-infected patients remains a challenge, as these patients are refractory to most therapies and develop liver fibrosis, cirrhosis and liver cancer more often than HCV mono-infected patients. Until the present study, there was no suitable in vitro assay to test the inhibitory activity of drugs on HCV/HIV-1 co-infection. Here we developed a novel in vitro "co-infection" model where HCV and HIV-1 concurrently replicate in their respective main host target cells--human hepatocytes and CD4+ T-lymphocytes. Using this co-culture model, we demonstrate that cyclophilin inhibitors (CypI), including a novel cyclosporin A (CsA) analog, CPI-431-32, simultaneously inhibits replication of both HCV and HIV-1 when added pre- and post-infection. In contrast, the HIV-1 protease inhibitor nelfinavir or the HCV NS5A inhibitor daclatasvir only blocks the replication of a single virus in the "co-infection" system. CPI-431-32 efficiently inhibits HCV and HIV-1 variants, which are normally resistant to DAAs. CPI-431-32 is slightly, but consistently more efficacious than the most advanced clinically tested CypI--alisporivir (ALV)--at interrupting an established HCV/HIV-1 co-infection. The superior antiviral efficacy of CPI-431-32 over ALV correlates with its higher potency inhibition of cyclophilin A (CypA) isomerase activity and at preventing HCV NS5A-CypA and HIV-1 capsid-CypA interactions known to be vital for replication of the respective viruses. Moreover, we obtained evidence that CPI-431-32 prevents the cloaking of both the HIV-1 and HCV genomes from cellular sensors. Based on these results, CPI-431-32 has the potential, as a single agent or in combination with DAAs, to inhibit both HCV and HIV-1 infections.

Amelioration of accelerated collagen induced arthritis by a novel calcineurin inhibitor, ISA(TX)247.

OBJECTIVE: To examine the efficacy and toxicity of ISA(TX)247, a novel calcineurin inhibitor, in comparison to cyclosporine (cyclosporin A, CSA) and placebo in established collagen induced arthritis. ISA(TX)247 has up to 3-fold greater potency than CSA in an in vitro whole blood calcineurin inhibition assay and in in vivo solid organ and cell transplantation models. Phase I clinical trials show no discernible nephrotoxicity. METHODS: Type II collagen immunized DBA/Lac J mice with established arthritis were randomized to treatment with ISA(TX)247 (125/250/500 microg/mouse), CSA (250/500 microg/mouse), or drug vehicle, by daily intraperitoneal injection for 10 days from the onset of clinical arthritis. RESULTS: A significant dose dependent reduction in clinical severity was observed in ISA(TX)247 treated but not in CSA treated animals 10 days after the onset of established arthritis, and when examined by area under the curve analysis during the treatment period. Significant improvement in paw swelling (p < 0.001), synovial histology (p < 0.001), and articular cartilage damage scores (p = 0.002) was also noted in ISA(TX)247 treated animals, even in the 125 pg dose group (p = 0.03 for paw swelling and synovial histology). By comparison, CSA had no significant effect on either synovial inflammation or articular cartilage damage. ISA(TX)247 (500 microg dose group) was the only treatment to significantly decrease the development of proximal interphalangeal joint erosions (p < 0.05). A significant reduction in Type II collagen antibody titer was noted in ISA(TX)247 animals in both 250 microg (p = 0.02) and 500 microg (p = 0.004) dosage groups, but only in the 500 microg group for CSA (p = 0.004). Treatment was well tolerated, with no significant toxicity in ISA(TX)247 groups. CONCLUSION: ISA(TX)247 demonstrates efficacy and safety in the treatment of established collagen induced arthritis. Together with its improved potency and nephrotoxicity profile in comparison to CSA, this agent warrants further clinical investigation in autoimmune disease. Phase II studies in rheumatoid arthritis have been initiated.