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Zheng J, Balsitis S, Santos R, Smith BJ, Subramanian R. Characterization of Seasonal Pharmacokinetic Variability in Woodchucks. Drug Metab Dispos 2020; 48:1199-1209. [PMID: 32892154 DOI: 10.1124/dmd.120.000140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 08/24/2020] [Indexed: 11/22/2022] Open
Abstract
The eastern woodchuck (Marmota monax) is a hibernating species extensively used as an in vivo efficacy model for chronic human hepatitis B virus infection. Under laboratory conditions, woodchucks develop a pseudohibernation condition; thus, the pharmacokinetics (PK) of small-molecule therapeutics may be affected by the seasonal change. The seasonal PK of four probe compounds were characterized over 12 months in seven male and nine female laboratory-maintained woodchucks. These compounds were selected to study changes in oxidative metabolism [antipyrine (AP)], glucuronidation [raltegravir (RTG)], renal clearance [lamivudine (3TC)], and hepatic function [indocyanine green (ICG)]. Seasonal changes in physiologic parameters and PK were determined. Seasonal body weight increases were ≥30%. Seasonal changes in body temperature and heart rate were <10%. The mean AP exposure remained unchanged from April to August 2017, followed by a significant increase (≥1.0-fold) from August to December and subsequent decrease to baseline at the end of study. A similar trend was observed in RTG and 3TC exposures. The ICG exposure remained unchanged. No significant sex difference in PK was observed, although female woodchucks appeared to be less susceptible to seasonal PK and body weight changes. Significant seasonal PK changes for AP, RTG, and 3TC indicate decreases in oxidative metabolism, phase II glucuronidation, and renal clearance during pseudohibernation. The lack of seasonal change in ICG exposure suggests there are no significant changes in hepatic function. This information can be used to optimize the scheduling of woodchuck studies to avoid seasonally driven variation in drug PK. SIGNIFICANCE STATEMENT: Woodchuck is a hibernating species and is commonly used as a nonclinical model of hepatitis B infection. Investigation of seasonal PK changes is perhaps of greater interest to pharmaceutical industry scientists, who use the woodchuck model to optimize the scheduling of woodchuck studies to avoid seasonally driven variation in drug PK and/or toxicity. This information is also valuable to drug metabolism and veterinary scientists in understanding woodchuck's seasonal metabolism and behavior under the pseudohibernation condition.
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Affiliation(s)
- Jim Zheng
- Gilead Sciences, Inc., Foster City, California
| | | | - Rex Santos
- Gilead Sciences, Inc., Foster City, California
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2
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Affiliation(s)
- Jonas J. Forsman
- Laboratory of Organic Chemistry, Åbo Akademi University, FI-20500 Åbo, Finland
| | - Reko Leino
- Laboratory of Organic Chemistry, Åbo Akademi University, FI-20500 Åbo, Finland
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3
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Torresi J, Locarnini SA. New therapeutic strategies in the treatment of hepatitis B virus infection. Expert Opin Investig Drugs 2005; 8:289-305. [PMID: 15992079 DOI: 10.1517/13543784.8.3.289] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Principally, because of the association of the chronic carrier state with the development of cirrhotic liver disease and hepatocellular carcinoma, chronic hepatitis B infection is a public health problem of global significance. In the main, therapy for chronic hepatitis B is limited to the use of alpha interferon for a limited number of chronic hepatitis B virus (HBV) carriers who have chronic hepatitis with active viral replication. The development of antiviral nucleoside analogues for the herpes viruses and human immunodeficiency virus (HIV) has resulted in the identification of several compounds which also have activity against HBV. Unfortunately, these agents have not been associated with the clearance of hepatitis B infection, but rather only the suppression of active infection while the patient is receiving medication. In addition, the development of drug-resistance to these agents by the virus will most likely limit their long-term efficacy. Gene therapy has recently been applied to HBV both in vitro and in vivo. This has included the use of antisense oligodeoxynucleotides and RNA, ribozymes, dominant negative mutants and therapeutic HBV vaccines. These newer therapeutic modalities may hold promise as effective treatments for chronic hepatitis B, but to date, have been limited by the problem of delivery to the target cell population or infected organ in vivo. Combination nucleoside analogue therapy may also provide an important treatment modality for chronic hepatitis B, although this will require further investigation.
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Affiliation(s)
- J Torresi
- Victorian Infectious Diseases Reference Laboratory, 10 Wreckyn Street, North Melbourne, Victoria, 3051, Australia.
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4
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Younger HM, Bathgate AJ, Hayes PC. Review article: Nucleoside analogues for the treatment of chronic hepatitis B. Aliment Pharmacol Ther 2004; 20:1211-30. [PMID: 15606384 DOI: 10.1111/j.1365-2036.2004.02211.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Current accepted treatment for chronic hepatitis B uses either the immunomodulator interferon alpha or nucleoside analogues lamivudine or adefovir. Interferon has side effects which mean it is often poorly tolerated. Long-term use of lamivudine is associated with increasing viral resistance for each year it is taken and the rebound viraemia that can occur when the drug is stopped is also of concern to many. Adefovir appears to have less of the resistance issues of lamivudine but is still a relatively new drug and at present its use is principally limited to patients with lamivudine-resistant disease. A number of other nucleoside analogues are currently being developed with some now at the stage of early clinical trials. A proportion share the significant resistance problems of lamivudine but many appear to have more potent anti-viral effect than the drugs currently available. If some of these newer anti-viral agents are approved for use in chronic hepatitis B, the potential for prolonged suppression of hepatitis B virus replication with resultant stabilization or improvement in liver disease may be achieved.
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Affiliation(s)
- H M Younger
- Liver Unit, Royal Infirmary of Edinburgh, Edinburgh, UK.
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5
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MESH Headings
- Adjuvants, Immunologic/therapeutic use
- Antiviral Agents/therapeutic use
- Carcinoma, Hepatocellular/etiology
- Carcinoma, Hepatocellular/physiopathology
- Carcinoma, Hepatocellular/prevention & control
- Hepacivirus/drug effects
- Hepacivirus/genetics
- Hepacivirus/physiology
- Hepatitis B virus/drug effects
- Hepatitis B virus/genetics
- Hepatitis B virus/physiology
- Hepatitis B, Chronic/complications
- Hepatitis B, Chronic/drug therapy
- Hepatitis B, Chronic/physiopathology
- Hepatitis C, Chronic/complications
- Hepatitis C, Chronic/drug therapy
- Hepatitis C, Chronic/physiopathology
- Humans
- Liver Cirrhosis/etiology
- Liver Cirrhosis/physiopathology
- Liver Cirrhosis/prevention & control
- Liver Neoplasms/etiology
- Liver Neoplasms/physiopathology
- Liver Neoplasms/prevention & control
- Reverse Transcriptase Inhibitors/therapeutic use
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Affiliation(s)
- Robert Y M Chen
- Victorian Infectious Diseases Reference Laboratory and St Vincent's Hospital,Melbourne, Victoria, Australia
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6
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Sznaidman ML, Almond MR, Pesyan A. New synthesis of L-FMAU from L-arabinose. NUCLEOSIDES, NUCLEOTIDES & NUCLEIC ACIDS 2002; 21:155-63. [PMID: 11991142 DOI: 10.1081/ncn-120003179] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
A new synthesis of 2'-deoxy-2'-fluoro-5-methyl-beta-L-arabinofuranosyl uracil (13, L-FMAU) was achieved in 10 steps from L-arabinose.
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Affiliation(s)
- Marcos L Sznaidman
- Division of Organic Chemistry, Triangle Pharmaceuticals Inc., RTP, North Carolina 27717, USA
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7
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Siatkosky LL, Shermock KM, Younossi ZM. Investigational pharmacologic treatment for liver disease. Expert Opin Investig Drugs 2002; 11:1281-93. [PMID: 12225249 DOI: 10.1517/13543784.11.9.1281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Liver disease can cause significant morbidity and mortality. Few pharmacological options exist for these diseases, however, new agents are in development and older agents are being evaluated for new indications. Several new nucleoside and nucleotide analogues are being developed to treat hepatitis B virus infection. Pegylated interferons have been developed for hepatitis C infection. Ursodeoxycholic acid has recently been implicated in the treatment of liver disease, including non-alcoholic steatohepatitis and primary sclerosing cholangitis.
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Khalili P, Naimi E, Knaus EE, Wiebe LI. Pharmacokinetics and metabolism of the novel synthetic C-nucleoside, 1-(2-deoxy-beta-D-ribofuranosyl)-2,4-difluoro-5-iodobenzene: a potential mimic of 5-iodo-2'-deoxyuridine. Biopharm Drug Dispos 2002; 23:105-13. [PMID: 12173545 DOI: 10.1002/bdd.301] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
1-(2-Deoxy-beta-D-ribofuranosyl)-2,4-difluoro-5-iodobenzene (5-IDFPdR) is one of the several unnatural 1-(2-deoxy-beta-D-ribofuranosyl)-2,4-difluoro-5-substituted-benzenes recently synthesized for evaluation as anticancer, antiviral and diagnostic imaging agents. This class of C-nucleosides was designed to exploit several potential advantages relative to classical 5-substituted-2'-deoxyuridines, including stability towards phosphorolysis by pyrimidine phosphorylase, increased lipophilicity that may alter their ability to cross the blood-brain-barrier, and a greater resistance towards catabolism and deiodination. The physiochemical evaluation of 5-IDFPdR showed high lipophilicity (log P = 2.8), moderately high protein binding (70-75%), stability towards phosphorolysis (e.g. no evidence of metabolic deglycosylation) by thymidine phosphorylase, and minimal microsomal metabolism in vitro. Pharmacokinetic studies of 5-IDFPdR in rat were characterized by a short elimination half-life (9-12 min), modest urinary elimination in pooled 0-24 h urine specimens (10-14%, including 2% as unconjugated drug) and high oral bioavailability (F = 0.96). Both glucuronide and sulfate metabolites were present in urine. Glucuronidation was the predominant conjugation pathway.
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Affiliation(s)
- Panteha Khalili
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Canada
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9
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Staschke KA, Colacino JM. Drug discovery and development of antiviral agents for the treatment of chronic hepatitis B virus infection. PROGRESS IN DRUG RESEARCH. FORTSCHRITTE DER ARZNEIMITTELFORSCHUNG. PROGRES DES RECHERCHES PHARMACEUTIQUES 2001; Spec No:111-83. [PMID: 11548207 DOI: 10.1007/978-3-0348-7784-8_4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A safe and effective vaccine for hepatitis B virus (HBV) has been available for nearly twenty years and currently campaigns to provide universal vaccination in developing countries are underway. Nevertheless, chronic HBV infection remains a leading cause of chronic hepatitis worldwide and there is a strong need for safe and effective antiviral therapies. Attempts to identify and develop antiviral agents to treat chronic HBV infection remains focused on nucleoside analogs such as 3TC (lamivudine), adefovir dipivoxil, (bis-POMPMEA), and others. However, advances in our understanding of the molecular biology of HBV and the development of new assays for HBV polymerase activity, such as the reconstitution of active HBV polymerase in vitro, should facilitate large screening efforts for non-nucleoside reverse transcriptase inhibitors. Recent advances have furthered our understanding of clinical resistance to lamivudine, have provided new approaches to treatment, and have offered new perspectives on the major challenges to the identification and development of antiviral agents for chronic HBV infection. Here, in an update to our previous review article that appeared in this series [59a], we focus on recent advances that have occurred in the areas of virus structure and replication, in vitro viral polymerase assays, cell culture systems, and animal models.
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Affiliation(s)
- K A Staschke
- Infectious Diseases Research, Lilly Research Laboratories, Indianapolis, IN, USA
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Zoulim F. Therapy of chronic hepatitis B virus infection: inhibition of the viral polymerase and other antiviral strategies. Antiviral Res 1999; 44:1-30. [PMID: 10588330 DOI: 10.1016/s0166-3542(99)00056-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Chronic hepatitis B infection remains a major public health problem worldwide. The hepatitis B virus belongs to the family of hepadnaviruses that replicate their DNA genome via a reverse transcription pathway. The chronicity of infection in infected hepatocytes is maintained by the persistence of the viral covalently closed circular DNA. The main strategies to combat chronic HBV infection rely on the stimulation of the specific antiviral immune response and on the inhibition of viral replication. While the prolonged administration of reverse transcriptase inhibitors is most often associated with a control of viral replication rather than eradication, it may select for resistant mutants. The search for new viral targets is therefore mandatory to design combination strategies to prevent the emergence of resistant mutants and eventually clear viral infection.
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11
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Du J, Choi Y, Lee K, Chun BK, Hong JH, Chu CK. A practical synthesis of L-FMAU from L-arabinose. NUCLEOSIDES & NUCLEOTIDES 1999; 18:187-95. [PMID: 10067271 DOI: 10.1080/15257779908043066] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
A practical synthesis of 2'-deoxy-2'-fluoro-5-methyl-beta-L-arabinofuranosyl uracil (14, L-FMAU) was developed from L-arabinose. L-Arabinose was converted to L-ribose 5, which was used for the synthesis of bromosugar 12 via 2,3,5-O-tribenzoyl-1-O-acetyl-beta-L-ribofuranose 8, which was subjected to condensation with silylated thymine and the resulting protected L-FMAU 13 was deprotected to afford L-FMAU in 14 steps in 8% overall yield.
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Affiliation(s)
- J Du
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens 30602, USA
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12
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Affiliation(s)
- P Wang
- Center for Drug Discovery, Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, The University of Georgia, Athens 30602-2352, USA
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13
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Colacino JM, Staschke KA. The identification and development of antiviral agents for the treatment of chronic hepatitis B virus infection. PROGRESS IN DRUG RESEARCH. FORTSCHRITTE DER ARZNEIMITTELFORSCHUNG. PROGRES DES RECHERCHES PHARMACEUTIQUES 1998; 50:259-322. [PMID: 9670781 DOI: 10.1007/978-3-0348-8833-2_6] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Hepatitis B virus (HBV) is the leading cause of chronic hepatitis throughout the world. Notwithstanding the availability of a safe and effective vaccine, the world prevalence of HBV has not declined significantly, thus resulting in the need for a selective antiviral agent. HBV is a small, partially double-stranded DNA virus which replicates through an RNA intermediate. Most efforts to develop anti-HBV agents have been targeted to the viral DNA polymerase which possesses reverse transcriptase activity. Currently, the most promising anti-HBV agents are nucleoside analogs which interfere with viral DNA replication. Although earlier nucleoside analogs such as vidarabine (ara-A) and fialuridine (FIAU) have displayed unacceptable toxicities, newer analogs such as lamivudine (3TC), bis-POM PMEA (GS-840), lobucavir, and BMS-200,475 have demonstrated clinical utility. In particular, the use of lamivudine has generated considerable interest in the development of other L-enantiomeric nucleoside analogs for use against HBV. Here, we provide an overview of HBV structure and replication strategy and discuss the use of cell culture systems, in vitro viral polymerase systems, and animal models to identify and evaluate anti-HBV agents. We also discuss the various classes of nucleoside analogs in terms of structure, mechanism of action, status in clinical development, ability to select for resistant HBV variants, and use in combination therapies. Finally, we present a discussion of novel antiviral approaches, including antisense and gene therapy, and address the various challenges to successful anti-HBV chemotherapeutic intervention.
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Affiliation(s)
- J M Colacino
- Infectious Diseases Research, Lilly Research Laboratories, Indianapolis, IN, USA
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14
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Abstract
In the past decade, significant progress has been achieved in the battle against hepatitis B virus. In addition to the immunomodulating agents such as interferon-alpha and thymosin, many novel antiviral agents have been discovered, among which nucleoside analogues are the mainstay. New-generation compounds such as 3TC and famciclovir have shown promise in the treatment of patients chronically infected by this virus, and are on the line for approval. However, viral rebound after cessation of therapy still remains a major problem. Additionally, the reports on the drug resistance to these antiviral agents suggest that combination therapy will be the eventual strategy (Bartholomew et al., 1997; Tipples et al., 1996). Therefore, developments of safe and effective antiviral agents which do not cross-resist with currently available antiviral drugs are still much needed.
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Affiliation(s)
- J H Hong
- Center for Drug Discovery, Pharmaceutical & Biomedical Sciences, College of Pharmacy, University of Georgia, Athens 30602-2352, USA
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15
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Advances in Nucleoside and Nucleotide Antiviral Therapies. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 1998. [DOI: 10.1016/s0065-7743(08)61081-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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