idx184 and Hepatitis-C

This article introduces one of the most diverse classes of direct-acting antivirals for hepatitis C, the nucleoside and non-nucleoside NS5B polymerase inhibitors. Through a systematic review of the published literature, we describe their structure, mechanism of action, issues with resistance, and clinical effectiveness shown in the latest clinical trials. Direct-acting antiviral combination trials that have already shown some early promising results even in the setting of interferon-sparing antiviral regimens are discussed.

Topics: Antiviral Agents; Clinical Trials as Topic; Deoxycytidine; Guanosine Monophosphate; Hepatitis C; Humans; Sofosbuvir; Uridine Monophosphate; Viral Nonstructural Proteins

IDX184 is a liver-targeted nucleotide prodrug that selectively inhibits HCV NS5B polymerase.. This randomized, double-blind, placebo-controlled, ascending-dose study investigated the antiviral activity, safety and pharmacokinetics of IDX184 plus pegylated interferon-α2a and ribavirin (P/R) in treatment-naive patients with genotype-1 HCV. A total of 81 patients with baseline HCV RNA≥5 log10 IU/ml, alanine aminotransferase ≤3× upper limit of normal and compensated liver disease were dosed. Sequential cohorts of 20 patients, randomized 16:4 (active:placebo), received IDX184 for 14 days at rising daily doses of 50, 100, 150 or 200 mg in combination with P/R for 14 days.. At the end of triple dosing, HCV RNA changes from baseline (mean ±sd log10) and proportion of patients achieving undetectable viral load (<15 IU/ml) based on the efficacy-evaluable population were -2.7 ±1.3 (13%), -4.0 ±1.7 (50%), -4.2 ±1.9 (50%), -4.1 ±1.2 (40%), -4.3 ±1.5 (29%) and -3.7 ±1.2 (25%) for the 50 mg once daily, 50 mg twice daily, 100 mg once daily, 150 mg once daily, 100 mg twice daily and 200 mg once daily IDX184 doses, respectively. P/R alone resulted in a reduction of -1.5 ±1.3 log10 with only 6% of patients with undetectable viral load. Patients with genotypes-1a or -1b responded similarly. No viral breakthrough or resistance associated with IDX184 was observed. Anti-HCV activity of IDX184 correlated with plasma exposure of its nucleoside metabolite 2'-methylguanosine. Most adverse events were mild or moderate in severity and were consistent with those associated with P/R. The most common adverse events were fatigue and headache.. IDX184 in combination with P/R for 14 days was well tolerated and demonstrated greater antiviral activity with more patients achieving undetectable viral load than P/R.

Topics: Adult; Antiviral Agents; Drug Interactions; Drug Therapy, Combination; Female; Genotype; Guanosine Monophosphate; Hepatitis C; Hepatitis C, Chronic; Humans; Interferon-alpha; Interferons; Interleukins; Male; Middle Aged; Polyethylene Glycols; Polymorphism, Genetic; Recombinant Proteins; Ribavirin; Treatment Outcome; Viral Load

IDX184 is a nucleotide prodrug designed to enhance formation in the liver of the active triphosphate of 2'-methylguanosine (2'-MeG), a potent and specific polymerase inhibitor of the hepatitis C virus (HCV). In the present study, single ascending oral doses of 5, 10, 25, 50, 75, and 100 mg IDX184 were administered sequentially to cohorts of 8 healthy subjects, randomized 6:2, active/placebo. Plasma and urine pharmacokinetic sampling was performed over a period of 120 h after dosing. Upon absorption, IDX184 rapidly disappeared from plasma, with a mean half-life (t(1/2)) of approximately 1 h, while plasma concentrations of 2'-MeG gradually increased. Consistent with a liver-targeting approach, plasma exposure of IDX184 and 2'-MeG was low and was also dose related: the mean maximum concentrations ranged from 1.1 to 17 ng/ml for IDX184 and 1.7 to 19 ng/ml for 2'-MeG, and the respective mean total area under the curve ranged from 1.2 to 22.7 and 17.3 to 334 ng·h/ml. Mean 2'-MeG plasma concentrations 24 h after dosing were 0.6 to 3 ng/ml for the 25- to 100-mg doses. Mean 2'-MeG t(1/2) values ranged from 18 to 43 h for doses of 25 mg and above. Mean cumulative urine excretion was 0.2% and 12 to 20% of administered doses for the unchanged IDX184 and 2'-MeG, respectively. IDX184 was safe and well tolerated; no serious adverse events (SAEs), dose-dependent adverse events (AEs), or dose-limiting toxicities were observed. The incidence of AEs and laboratory abnormalities was low and was similar among subjects receiving IDX184 or a placebo. All AEs were mild to moderate and resolved at the end of study. The favorable safety and pharmacokinetic profiles support further clinical evaluation of IDX184 in HCV-infected patients.

Topics: Adult; Aged; Antiviral Agents; Female; Guanosine Monophosphate; Hepacivirus; Hepatitis C; Humans; Male; Middle Aged; Placebos; Young Adult

In the last few months, a new Zika virus (ZIKV) outbreak evolved in America. In accordance, World Health Organization (WHO) in February 2016 declared it as Public Health Emergency of International Concern (PHEIC). ZIKV infection was reported in more than 60 countries and the disease was spreading since 2007 but with little momentum. Many antiviral drugs are available in market or in laboratories under clinical trials, could affect ZIKV infection. In silico docking study were performed on the ZIKV polymerase to test some of Hepatitis C Virus (HCV) drugs (approved and in clinical trials). The results show potency of almost all of the studied compounds on ZIKV polymerase and hence inhibiting the propagation of the disease. In addition, the study suggested two nucleotide inhibitors (IDX-184 and MK0608) that may be tested as drugs against ZIKV infection. J. Med. Virol. 88:2044-2051, 2016. © 2016 Wiley Periodicals, Inc.

Topics: Antiviral Agents; Clinical Trials as Topic; Computer Simulation; Drug Discovery; Enzyme Inhibitors; Guanosine Monophosphate; Hepacivirus; Hepatitis C; Humans; Molecular Docking Simulation; RNA-Dependent RNA Polymerase; Tubercidin; Zika Virus; Zika Virus Infection

A conventional, rapid and high throughput method for tissue extraction and accurate and selective LC-MS/MS quantification of 2'-C-methylguanosine triphosphate (2'-MeGTP) in mouse liver was developed and qualified. Trichloroacetic acid (TCA) was used as the tissue homogenization reagent that overcomes instability challenges of liver tissue nucleotide triphosphates due to instant ischemic degradation to mono- and diphosphate nucleotides. Degradation of 2'-MeGTP was also minimized by harvesting livers using in situ clamp-freezing or snap-freezing techniques. The assay also included a sample clean-up procedure using weak anion exchange solid phase extraction followed by ion exchange chromatography and tandem mass spectrometry detection. The linear assay range was from 50 to 10000 pmol/mL concentration in liver homogenate (250-50000 pmol/g in liver tissue). The method was qualified over three intraday batches for accuracy, precision, selectivity and specificity. The assay was successfully applied to pharmacokinetic studies of 2'-MeGTP in liver tissue samples after single oral doses of IDX184, a nucleotide prodrug inhibitor of the viral polymerase for the treatment of hepatitis C, to mice. The study results suggested that the clamp-freezing liver collection method was marginally more effective in preventing 2'-MeGTP degradation during liver tissue collection compared to the snap-freezing method.

Topics: Animals; Antiviral Agents; Chromatography, Ion Exchange; Chromatography, Liquid; Freezing; Guanosine; Guanosine Monophosphate; Guanosine Triphosphate; Hepatitis C; Liver; Male; Mice; Nucleotides; Prodrugs; Solid Phase Extraction; Tandem Mass Spectrometry; Trichloroacetic Acid

Ribonucleoside analogs possessing a β-methyl substituent at the 2'-position of the d-ribose moiety have been previously discovered to be potent and selective inhibitors of hepatitis C virus (HCV) replication, their triphosphates acting as alternative substrate inhibitors of the HCV RdRp NS5B. Results/methodology: In this article, the authors detail the synthesis, anti-HCV evaluation in cell-based replicon assays and structure-activity relationships of several phosphoramidate diester derivatives of 2'-C-methylguanosine (2'-MeG).. The most promising compound, namely the O-[S-(hydroxyl)pivaloyl-2-thioethyl]{abbreviated as O-[(HO)tBuSATE)]} N-benzylamine phosphoramidate diester derivative (IDX184), was selected for further in vivo studies, and was the first clinical pronucleotide evaluated for the treatment of chronic hepatitis C up to Phase II trials.

Topics: Antiviral Agents; Drug Discovery; Guanosine Monophosphate; Hepacivirus; Hepatitis C; Humans; Structure-Activity Relationship

We have previously reported the power of combining a 5'-phosphoramidate ProTide, phosphate pro-drug, motif with a 6-methoxy purine pro-drug entity to generate highly potent anti-HCV agents, leading to agents in clinical trial. We herein extend this work with the disclosure that a variety of alternative 6-substituents are tolerated. Several compounds exceed the potency of the prior 6-methoxy leads, and in almost every case the ProTide is several orders of magnitude more potent than the parent nucleoside. We also demonstrate that these agents act as pro-drugs of 2'-C-methyl guanosine monophosphate. We have also reported the novel use of hepatocyte cell lysate as an ex vivo model for ProTide metabolism.

Topics: Amides; AMP Deaminase; Antiviral Agents; Cell Line, Tumor; Drug Design; Drug Evaluation, Preclinical; Guanosine Monophosphate; Hepacivirus; Hepatitis C; Humans; Hydrolysis; Inhibitory Concentration 50; Microbial Sensitivity Tests; Molecular Structure; Nucleosides; Phosphoric Acids; Phosphorylation; Prodrugs; Stereoisomerism; Structure-Activity Relationship; Virus Replication