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Biochemical Characterization of the Active Anti-Hepatitis C Virus Metabolites of 2,6-Diaminopurine Ribonucleoside Prodrug Compared to Sofosbuvir and BMS-986094. Antimicrob Agents Chemother 2016; 60:4659-69. [PMID: 27216050 DOI: 10.1128/aac.00318-16] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 05/12/2016] [Indexed: 12/20/2022] Open
Abstract
Ribonucleoside analog inhibitors (rNAI) target the hepatitis C virus (HCV) RNA-dependent RNA polymerase nonstructural protein 5B (NS5B) and cause RNA chain termination. Here, we expand our studies on β-d-2'-C-methyl-2,6-diaminopurine-ribonucleotide (DAPN) phosphoramidate prodrug 1 (PD1) as a novel investigational inhibitor of HCV. DAPN-PD1 is metabolized intracellularly into two distinct bioactive nucleoside triphosphate (TP) analogs. The first metabolite, 2'-C-methyl-GTP, is a well-characterized inhibitor of NS5B polymerase, whereas the second metabolite, 2'-C-methyl-DAPN-TP, behaves as an adenosine base analog. In vitro assays suggest that both metabolites are inhibitors of NS5B-mediated RNA polymerization. Additional factors, such as rNAI-TP incorporation efficiencies, intracellular rNAI-TP levels, and competition with natural ribonucleotides, were examined in order to further characterize the potential role of each nucleotide metabolite in vivo Finally, we found that although both 2'-C-methyl-GTP and 2'-C-methyl-DAPN-TP were weak substrates for human mitochondrial RNA (mtRNA) polymerase (POLRMT) in vitro, DAPN-PD1 did not cause off-target inhibition of mtRNA transcription in Huh-7 cells. In contrast, administration of BMS-986094, which also generates 2'-C-methyl-GTP and previously has been associated with toxicity in humans, caused detectable inhibition of mtRNA transcription. Metabolism of BMS-986094 in Huh-7 cells leads to 87-fold higher levels of intracellular 2'-C-methyl-GTP than DAPN-PD1. Collectively, our data characterize DAPN-PD1 as a novel and potent antiviral agent that combines the delivery of two active metabolites.
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Bonaventura A, Montecucco F. Sofosbuvir/velpatasvir: A promising combination. World J Hepatol 2016; 8:785-789. [PMID: 27429714 PMCID: PMC4937166 DOI: 10.4254/wjh.v8.i19.785] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 05/23/2016] [Accepted: 06/16/2016] [Indexed: 02/06/2023] Open
Abstract
Hepatitis C virus (HCV) affects 3% of the world population. It represents the main cause of chronic liver disease and is responsible for extra-hepatic complications, such as type 2 diabetes and cardiovascular diseases. HCV includes 7 genotypes differing in the nucleotide sequence variability, the geographic distribution, the rates of viral clearance, the risk of progression to liver fibrosis and to hepatocellular carcinoma, and the response to therapy. Last years have seen remarkable advances in the field of HCV infection with the approval of direct antiviral agents (DAAs) targeting key viral proteins involved in the HCV replication. Several oral regimens combining DAAs from different families have been developed and these regimens showed increased and sustained virological response rates to above 90% reducing the treatment duration to 12 wk or less. In particular, sofosbuvir, a nucleotide analogue nonstructural (NS)5B polymerase inhibitor, and velpatasvir, a NS5A inhibitor, have been tested in two phase 3 trials, the ASTRAL-2 (against HCV genotype 2) and the ASTRAL-3 (against HCV genotype 3), demonstrating to be effective, safe, and well tolerated in patients who were 18 years of age or older and had at least a 6-mo history of HCV infection with a compensated liver disease.
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Sully EK, Geller BL. Antisense antimicrobial therapeutics. Curr Opin Microbiol 2016; 33:47-55. [PMID: 27375107 PMCID: PMC5069135 DOI: 10.1016/j.mib.2016.05.017] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 05/17/2016] [Accepted: 05/31/2016] [Indexed: 01/17/2023]
Abstract
Antisense antimicrobial therapeutics are synthetic oligomers that silence expression of specific genes. This specificity confers an advantage over broad-spectrum antibiotics by avoiding unintended effects on commensal bacteria. The sequence-specificity and short length of antisense antimicrobials also pose little risk to human gene expression. Because antisense antimicrobials are a platform technology, they can be rapidly designed and synthesized to target almost any microbe. This reduces drug discovery time, and provides flexibility and a rational approach to drug development. Recent work has shown that antisense technology has the potential to address the antibiotic-resistance crisis, since resistance mechanisms for standard antibiotics apparently have no effect on antisense antimicrobials. Here, we describe current reports of antisense antimicrobials targeted against viruses, parasites, and bacteria.
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Affiliation(s)
- Erin K Sully
- Department of Microbiology, 226 Nash Hall, Oregon State University, Corvallis, OR 97331-3804, USA
| | - Bruce L Geller
- Department of Microbiology, 226 Nash Hall, Oregon State University, Corvallis, OR 97331-3804, USA.
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Recent Advances in Antiviral Therapy for Chronic Hepatitis C. Mediators Inflamm 2016; 2016:6841628. [PMID: 27022210 PMCID: PMC4752984 DOI: 10.1155/2016/6841628] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 01/06/2016] [Indexed: 12/11/2022] Open
Abstract
Hepatitis C virus (HCV) infection is a major worldwide health problem. Chronic infection induces continuous inflammation in the liver, progression of hepatic fibrosis, eventual cirrhosis, and possible hepatocellular carcinoma. Eradication of the virus is one of the most important treatment aims. A number of promising new direct-acting antivirals (DAAs) have been developed over the past 10 years. Due to their increased efficacy, safety, and tolerability, interferon-free oral therapies with DAAs have been approved for patients with HCV, including those with cirrhosis. This review introduces the characteristics and results of recent clinical trials of several DAAs: NS3/4A protease inhibitors, NS5A inhibitors, and NS5B inhibitors. DAA treatment failure and prognosis after DAA therapy are also discussed.
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Neelamkavil SF, Agrawal S, Bara T, Bennett C, Bhat S, Biswas D, Brockunier L, Buist N, Burnette D, Cartwright M, Chackalamannil S, Chase R, Chelliah M, Chen A, Clasby M, Colandrea VJ, Davies IW, Eagen K, Guo Z, Han Y, Howe J, Jayne C, Josien H, Kargman S, Marcantonio K, Miao S, Miller R, Nolting A, Pinto P, Rajagopalan M, Ruck RT, Shah U, Soriano A, Sperbeck D, Velazquez F, Wu J, Xia Y, Venkatraman S. Discovery of MK-8831, A Novel Spiro-Proline Macrocycle as a Pan-Genotypic HCV-NS3/4a Protease Inhibitor. ACS Med Chem Lett 2016; 7:111-6. [PMID: 26819676 DOI: 10.1021/acsmedchemlett.5b00425] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 12/22/2015] [Indexed: 01/31/2023] Open
Abstract
We have been focused on identifying a structurally different next generation inhibitor to MK-5172 (our Ns3/4a protease inhibitor currently under regulatory review), which would achieve superior pangenotypic activity with acceptable safety and pharmacokinetic profile. These efforts have led to the discovery of a novel class of HCV NS3/4a protease inhibitors containing a unique spirocyclic-proline structural motif. The design strategy involved a molecular-modeling based approach, and the optimization efforts on the series to obtain pan-genotypic coverage with good exposures on oral dosing. One of the key elements in this effort was the spirocyclization of the P2 quinoline group, which rigidified and constrained the binding conformation to provide a novel core. A second focus of the team was also to improve the activity against genotype 3a and the key mutant variants of genotype 1b. The rational application of structural chemistry with molecular modeling guided the design and optimization of the structure-activity relationships have resulted in the identification of the clinical candidate MK-8831 with excellent pan-genotypic activity and safety profile.
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Affiliation(s)
| | - Sony Agrawal
- Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Thomas Bara
- Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Chad Bennett
- Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Sathesh Bhat
- Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Dipshikha Biswas
- Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Linda Brockunier
- Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Nicole Buist
- Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Duane Burnette
- Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Mark Cartwright
- Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | | | - Robert Chase
- Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Mariappan Chelliah
- Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Austin Chen
- Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Martin Clasby
- Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | | | - Ian W. Davies
- Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Keith Eagen
- Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Zhuyan Guo
- Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Yongxin Han
- Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - John Howe
- Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Charles Jayne
- Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Hubert Josien
- Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Stacia Kargman
- Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Karen Marcantonio
- Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Shouwu Miao
- Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Randy Miller
- Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Andrew Nolting
- Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Patrick Pinto
- Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Murali Rajagopalan
- Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Rebecca T. Ruck
- Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Unmesh Shah
- Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Aileen Soriano
- Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Donald Sperbeck
- Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | | | - Jin Wu
- Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Yan Xia
- Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
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